Ignore more Gradle build artifacts in Android project

[brodycj]

I hope we can get this in before the next major release for Cordova 9 (apache/cordova#10).

P..S. These artifacts are generated by Gradle when the user does cordova build android or cordova run android.

[codecov-io]

Codecov Report

Merging #632 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #632   +/-   ##
=======================================
  Coverage   64.66%   64.66%           
=======================================
  Files          18       18           
  Lines        1817     1817           
=======================================
  Hits         1175     1175           
  Misses        642      642

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7a98708...b263d0a. Read the comment docs.

[janpio]

That PR description is a bit light on information.

Why wasn't this in there before? Why should this be in now? Are those new files? Or was this just missed before?

There is also a merge conflict that has to be resolved.

[brodycj]

I just added the info to the description and resolved the conflict. I hope it is clear now, would be happy to answer any other questions.

[janpio]

Ok, this matches a popular gitignore suggestion for Gradle:
https://github.com/github/gitignore/blob/master/Gradle.gitignore

And /app/build seems to be "new" because of the move of the project into app, in some earlier time it was probably all generated in /build.

[brodycj]

Thanks @janpio! I didn't see that link before, just added a couple more artifacts.

[janpio]

Umm, do we actually have those? Otherwise those are not really necessary to include. But well, it's merged already.