Upgrade to Gradle 8.5 and Gradle Plugin 8.3.0 for compatibility with Java 21. Explicity set Java version 21 in `build.gradle`. Increment compile and target SDK version to 34 accordingly.
Remove the explicitly defined, obsolete `buildToolsVersion` property in `build.gradle`, as it is now automatically derived by Gradle.
Replace the deprecated property `android:extractNativeLibs` in `AndroidMainfest.xml` with `useLegacyPackaging` in `build.gradle`.
Replace the deprecated package definition `package="tw.DDNet"` in `AndroidMainfest.xml` with `namespace("tw.DDNet")` in `build.gradle`.
Add the required property `android:exported="true"` to the main activity in `AndroidMainfest.xml`.
