dependency: bump sonar-packaging-maven-plugin

Bumps [sonar-packaging-maven-plugin](https://github.com/SonarSource/sonar-packaging-maven-plugin) from 1.17 to 1.21.0.505.
- [Release notes](https://github.com/SonarSource/sonar-packaging-maven-plugin/releases)
- [Commits](SonarSource/sonar-packaging-maven-plugin@1.17...1.21.0.505)

---
updated-dependencies:
- dependency-name: org.sonarsource.sonar-packaging-maven-plugin:sonar-packaging-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

sevntu-checkstyle-sonar-plugin/pom.xml

@@ -141,7 +141,7 @@
       <plugin>
         <groupId>org.sonarsource.sonar-packaging-maven-plugin</groupId>
         <artifactId>sonar-packaging-maven-plugin</artifactId>
-        <version>1.17</version>
+        <version>1.21.0.505</version>
         <extensions>true</extensions>
         <configuration>
           <pluginClass>com.github.sevntu.checkstyle.sonar.CheckstyleExtensionPlugin</pluginClass>