Add in app update

[tobioyelekan]

Description

Closes #378
Add android app update
Needs to be tested well with internal app sharing https://developer.android.com/guide/playcore/in-app-updates/test

Checklist

• I have read the contribution guidelines: https://github.com/permissionlesstech/bitchat-android?tab=readme-ov-file#contributing
• I have performed a self-review of my code

• I have mentioned the corresponding issue and the relevant keyword (e.g., "Closes: #xy") in the description (see https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)

[callebtc]

thank you for this PR, how do I test this?

[tobioyelekan]

thank you for this PR, how do I test this?

Hi @callebtc, you can test it through the internal app sharing track on playstore. Basically, you have to upload two builds with the in-app update to internal sharing - one higher than the other. Install the lower version, ensure you can open the second version(you can copy the link from playstore), and you can see "update" on playstore(don't update from there). Then close and re-open the old version. The update dialog should pop-up.

I provided a link already in the PR description, but here's a more detailed step by step you could follow (not much)
https://medium.com/@wandering.soul/step-by-step-guide-to-test-in-app-update-implementation-68f9ed3619c

If you're open to it, you could invite me as a tester so I can help verify it.