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: Automatic version bumping vitabu#96 (review)

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

• content-provider
  • Document steps for releasing a new version content-provider#88
  • Add version upgrade functionality content-provider#90
• analytics
  • Automate Gradle releases analytics#135
• herufi
  • Automate Gradle releases 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? 🙂