Fix signing configuration and change target/source compat to 18

.github/workflows/build_and_sign.yml

@@ -1,4 +1,4 @@
-name: Android CI
+name: Build Signed Release
 
 on:
   push:

build.gradle

@@ -80,25 +80,25 @@ android {
     }
 
     compileOptions {
-        sourceCompatibility = 17
-        targetCompatibility = 17
+        sourceCompatibility = 18
+        targetCompatibility = 18
     }
 
     signingConfigs {
-        if (project.hasProperty('RELEASE_STORE_FILE')) {
+        if (System.getenv('RELEASE_STORE_FILE') != null) {
             release {
-                storeFile file(RELEASE_STORE_FILE)
-                storePassword RELEASE_STORE_PASSWORD
-                keyAlias RELEASE_KEY_ALIAS
-                keyPassword RELEASE_KEY_PASSWORD
+                storeFile file(System.getenv("RELEASE_STORE_FILE"))
+                storePassword System.getenv("RELEASE_STORE_PASSWORD")
+                keyAlias System.getenv("RELEASE_KEY_ALIAS")
+                keyPassword System.getenv("RELEASE_KEY_PASSWORD")
             }
         }
     }
 
     buildTypes {
         release {
             buildConfigField "boolean", "ALWAYS_UPGRADE", "false"
-            if (project.hasProperty('RELEASE_STORE_FILE')) {
+            if (System.getenv('RELEASE_STORE_FILE') != null) {
                 signingConfig signingConfigs.release
             }
         }