Hardcode Android RN version in bridge and aztec

[mchowning]

Before this fix, building the Android react-native-gutenberg-bridge or react-native-aztec modules directly (i.e., where they are the rootProject) would use an older version of react native. With a recent change to the project this resulted in a build error. Jitpack builds those modules directly, so builds on Jitpack were failing.

This is a temporary fix to get the Jitpack builds back to green while I work on a solution that doesn't use hardcoded values. I expect to open a new PR with a cleaner solution later today.

I'm not updating the value in the relevant package.json files in this temporary-fix-PR because it seems that we need version v0.60.0-patched in the package.json files, but we need to drop the v for the java dependency version.

To test:

• Verify app builds and runs both locally and on Jitpack. I had Jitpack complete a build of this commit (f031379) before opening this PR: https://jitpack.io/#wordpress-mobile/gutenberg-mobile

PR submission checklist:

• I have considered adding unit tests where possible.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[cameronvoell]

Verified the example app and WordPress Android app build locally with this change, and noted the successful green build on jitpack.