[pigeon]: Bump org.jetbrains.kotlin:kotlin-gradle-plugin from 1.9.20 …

…to 1.9.21 in /packages/pigeon/platform_tests/test_plugin/android (flutter#5483)

Bumps [org.jetbrains.kotlin:kotlin-gradle-plugin](https://github.com/JetBrains/kotlin) from 1.9.20 to 1.9.21.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/JetBrains/kotlin/releases">org.jetbrains.kotlin:kotlin-gradle-plugin's releases</a>.</em></p>
<blockquote>
<h2>Kotlin 1.9.21</h2>
<h2>Changelog</h2>
<h3>Compiler</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62885"><code>KT-62885</code></a> Introduce a language feature entry for expect actual classes for easier configuration of MPP projects</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63081"><code>KT-63081</code></a> Optimize new native caches: CachedLibraries.computeVersionedCacheDirectory()</li>
</ul>
<h3>Docs &amp; Examples</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-55619"><code>KT-55619</code></a> Document <code>String.format</code> function</li>
</ul>
<h3>IDE. Gradle Integration</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62877"><code>KT-62877</code></a> Artifact files collecting for project configuration was finished. Resolution for configuration configuration  X will be skipped</li>
</ul>
<h3>IDE. Gradle. Script</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-60813"><code>KT-60813</code></a> Scripts: NoSuchMethodError: 'void org.slf4j.Logger.error(java.lang.String, java.lang.Object)' when dependency uses Slf4j API</li>
</ul>
<h3>JavaScript</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-60785"><code>KT-60785</code></a> KJS: Destructured value class in suspend function fails with Uncaught TypeError: can't convert to primitive type error</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62778"><code>KT-62778</code></a> package.json &quot;main&quot; field has .js extension when the result files have .mjs extension</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-61795"><code>KT-61795</code></a> KJS: Incremental Cache is not invalidated if <code>useEsClasses</code> compiler argument was changed</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-61957"><code>KT-61957</code></a> KJS: &quot;Uncaught ReferenceError: entries is not defined&quot; caused by enum class with <code>@JsExport</code> and Enum.entries call</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62444"><code>KT-62444</code></a> KJS with commonJS modules should re-export in 1.9.20</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63184"><code>KT-63184</code></a> KJS / Serialization: JsExport on serializable interface creates erroneous TypeScript</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62190"><code>KT-62190</code></a> KJS: &quot;IllegalStateException: Expect to have either super call or partial linkage stub inside constructor&quot; caused by Compose and useEsModules()</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58685"><code>KT-58685</code></a> KJS: &quot;IllegalStateException: Not locked&quot; cused by &quot;unlock&quot; called twice</li>
</ul>
<h3>Klibs</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62515"><code>KT-62515</code></a> Interop klib of concurrent version is not accepted when building dependent project: &quot;The library versions don't match&quot;</li>
</ul>
<h3>Tools. CLI</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63139"><code>KT-63139</code></a> Incorrect kotlin implementation version (1.9.255-SNAPSHOT) in metadata info</li>
</ul>
<h3>Tools. Gradle</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63499"><code>KT-63499</code></a> Gradle: Source sets conventions are still registered</li>
</ul>
<h3>Tools. Gradle. JS</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-59523"><code>KT-59523</code></a> MPP / KJS: ESM modules uses incorrect file extension on package.json (.mjs)</li>
</ul>
<h3>Tools. Gradle. Kapt</h3>
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a href="https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md">org.jetbrains.kotlin:kotlin-gradle-plugin's changelog</a>.</em></p>
<blockquote>
<h2>1.9.21</h2>
<h3>Compiler</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62885"><code>KT-62885</code></a> Introduce a language feature entry for expect actual classes for easier configuration of MPP projects</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63081"><code>KT-63081</code></a> Optimize new native caches: CachedLibraries.computeVersionedCacheDirectory()</li>
</ul>
<h3>Docs &amp; Examples</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-55619"><code>KT-55619</code></a> Document <code>String.format</code> function</li>
</ul>
<h3>IDE. Gradle Integration</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62877"><code>KT-62877</code></a> Artifact files collecting for project configuration was finished. Resolution for configuration configuration  X will be skipped</li>
</ul>
<h3>IDE. Gradle. Script</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-60813"><code>KT-60813</code></a> Scripts: NoSuchMethodError: 'void org.slf4j.Logger.error(java.lang.String, java.lang.Object)' when dependency uses Slf4j API</li>
</ul>
<h3>JavaScript</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-60785"><code>KT-60785</code></a> KJS: Destructured value class in suspend function fails with Uncaught TypeError: can't convert to primitive type error</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62778"><code>KT-62778</code></a> package.json &quot;main&quot; field has .js extension when the result files have .mjs extension</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-61795"><code>KT-61795</code></a> KJS: Incremental Cache is not invalidated if <code>useEsClasses</code> compiler argument was changed</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-61957"><code>KT-61957</code></a> KJS: &quot;Uncaught ReferenceError: entries is not defined&quot; caused by enum class with <code>@JsExport</code> and Enum.entries call</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62444"><code>KT-62444</code></a> KJS with commonJS modules should re-export in 1.9.20</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63184"><code>KT-63184</code></a> KJS / Serialization: JsExport on serializable interface creates erroneous TypeScript</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62190"><code>KT-62190</code></a> KJS: &quot;IllegalStateException: Expect to have either super call or partial linkage stub inside constructor&quot; caused by Compose and useEsModules()</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58685"><code>KT-58685</code></a> KJS: &quot;IllegalStateException: Not locked&quot; cused by &quot;unlock&quot; called twice</li>
</ul>
<h3>Klibs</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-62515"><code>KT-62515</code></a> Interop klib of concurrent version is not accepted when building dependent project: &quot;The library versions don't match&quot;</li>
</ul>
<h3>Tools. CLI</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63139"><code>KT-63139</code></a> Incorrect kotlin implementation version (1.9.255-SNAPSHOT) in metadata info</li>
</ul>
<h3>Tools. Gradle</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63499"><code>KT-63499</code></a> Gradle: Source sets conventions are still registered</li>
</ul>
<h3>Tools. Gradle. JS</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-59523"><code>KT-59523</code></a> MPP / KJS: ESM modules uses incorrect file extension on package.json (.mjs)</li>
</ul>
<h3>Tools. Gradle. Kapt</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-63366"><code>KT-63366</code></a> Kapt processing fails with custom source sets</li>
</ul>
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/JetBrains/kotlin/commit/b2740d8957b6af072340b7aab0a50ccba4e5fbcc"><code>b2740d8</code></a> Add changelog for 1.9.21</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/5d6520c9fb0e0dc22ceeca77b848484e128854c5"><code>5d6520c</code></a> [K/JS] Fix coroutines but turn back the fix for coroutines intrinsics `interc...</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/8293c8f538ef2002f57303b3f1fc932ad87dd89d"><code>8293c8f</code></a> KAPT: Use reflection to access code, changed in JDK 21</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/e459a6d5d2f23331cbcae4d4d06b9b3d295c7d4e"><code>e459a6d</code></a> KAPT: Always print parens on empty annotation parameters</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/705c8047aec3298ecb803df6ba12da88509c7eeb"><code>705c804</code></a> KAPT: Run tests on JDK 21</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/120c99d4550b07614c4d7e8bd1100560f1f89da7"><code>120c99d</code></a> Fix ClassCastException in JPS statistics ad update log messages</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/68f26183f887dd8f74b95bc901082529f6c7c7c3"><code>68f2618</code></a> Fix ClassCastException in JPS statistics ad update log messages</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/c66b789f93fd0387cd7d7775ce2d15d1a8eda0ff"><code>c66b789</code></a> KAPT3: Use another class in com.sun.tools.javac.main</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/d4ce8c72621b3a7273c5c44cf1543e53c5d9d20c"><code>d4ce8c7</code></a> Temporarily disable Kapt4IT and KaptIncrementalIT and the descendants.</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/f559dd55abe9f0b01af0d81cdaf2854ffa5b357d"><code>f559dd5</code></a> Stop using IJ's maps in graph implementation of JPS</li>
<li>Additional commits viewable in <a href="https://github.com/JetBrains/kotlin/compare/v1.9.20...v1.9.21">compare view</a></li>
</ul>
</details>
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packages/pigeon/platform_tests/test_plugin/android/build.gradle

@@ -2,7 +2,7 @@ group 'com.example.test_plugin'
 version '1.0-SNAPSHOT'
 
 buildscript {
-    ext.kotlin_version = '1.9.20'
+    ext.kotlin_version = '1.9.21'
     repositories {
         google()
         mavenCentral()