Automate Gradle releases for Android apps

[nya-elimu]

Add a GitHub Action workflow for automatically performing a Gradle release each time a pull request is merged into main for these Android apps:

• vitabu
  Note that automatic Gradle version bumping has been implemented for this app already: elimu-ai/vitabu#96 (review)

Once it works with the Vitabu app, copy the same solution to these apps:

• content-provider
  • elimu-ai/content-provider#88
  • elimu-ai/content-provider#90
• analytics
  • elimu-ai/analytics#135
• herufi
  • elimu-ai/herufi#13

[vivekkiran]

I am interested in this task.

[nya-elimu]

@vivekkiran Great! Sent you an invite to join the GitHub organization 🙂

[nya-elimu]

@vivekkiran Are you still interested?

[nya-elimu]

@vivekkiran? 🙂