fix: gradle deprecation warnings about property assignment (#1821)

When building a plain Android Cordova app without plugins, there will be Gradle depraction warnings: `Deprecated Gradle features were used in this build, making it incompatible with Gradle 9.0.`. Compiling it with `--warning-mode all` shows, that some properties are assigned without an `=`, which will not be supported any longer with Gradle 10.0.

templates/project/app/build.gradle

@@ -183,10 +183,10 @@ task cdvPrintProps {
 }
 
 android {
-    namespace cordovaConfig.PACKAGE_NAMESPACE
+    namespace = cordovaConfig.PACKAGE_NAMESPACE
 
     buildFeatures {
-        buildConfig true
+        buildConfig = true
     }
 
     defaultConfig {
@@ -202,7 +202,7 @@ android {
     }
 
     lintOptions {
-      abortOnError false
+      abortOnError = false
     }
 
     buildToolsVersion cordovaConfig.BUILD_TOOLS_VERSION