Fix part of #4251: Update app version name & codes for alpha MR4

[BenHenning]

Explanation

Fix part of #4251

This bumps the minor version & related version codes in preparation for cutting alpha MR4. Note that the extra '+4' is because we shipped a prerelease version of the app and didn't correspondingly commit the increment (normally we increment the version codes by +4 since there are 4 flavors built in each release, but we didn't account for the 4 used in the prerelease version).

Furthermore, alpha MR4 will include an extra version for an upcoming research study project, so the version codes will need to be incremented an extra '+1' next time (this is tracked by #4348).

Essential Checklist

• The PR title and explanation each start with "Fix #bugnum: " (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• Any changes to scripts/assets files have their rationale included in the PR explanation.
• The PR follows the style guide.
• The PR does not contain any unnecessary code changes from Android Studio (reference).
• The PR is made from a branch that's not called "develop" and is up-to-date with "develop".
• The PR is assigned to the appropriate reviewers (reference).

For UI-specific PRs only

N/A

[BenHenning]

@seanlip PTAL.

/cc @ankita240796 for FYI.

[rt4914]

@BenHenning I am unable to understand the PR decription. It says +4 but the PR has +8

[BenHenning]

I updated the description to clarify @rt4914. PTAL and let me know if that's clear, or if more context is needed.

[rt4914]

Lgtm thanks

[oppiabot]

Unassigning @BenHenning since a re-review was requested. @BenHenning, please make sure you have addressed all review comments. Thanks!

[BenHenning]

Thanks @rt4914!