Gson 2.13.1

What's Changed

Give FieldNamingStrategy the ability to return multiple String names by @mfriesen in https://github.com/google/gson/pull/2776
Remove outdated android-proguard-example by @Goooler in https://github.com/google/gson/pull/2843
Adjust Troubleshooting Guide ProGuard / R8 section by @Marcono1234 in https://github.com/google/gson/pull/2844
Update dependencies, including the problematic com.google.errorprone:error_prone_annotations:2.37.0.

@mfriesen made their first contribution in https://github.com/google/gson/pull/2776
@Goooler made their first contribution in https://github.com/google/gson/pull/2843

Full Changelog: https://github.com/google/gson/compare/gson-parent-2.13.0...gson-parent-2.13.1