Build fails with Java 25 due to unsupported class file version

The build fails with java 25

```
./gradlew assembleFullDebug
...
FAILURE: Build failed with an exception.

* What went wrong:
Could not open settings generic class cache for settings file '/home/bwitt/src/transdroid/settings.gradle'
> BUG! exception in phase 'semantic analysis' in source unit '_BuildScript_'
  Unsupported class file major version 69
...
```


