Create CI workflow with GitHub Actions

[EwoutH]

Create CI workflow with GitHub Actions which:

• Builds the encoder and decoder for Android
• Builds the Android APK and uploads it to GitHub as build artifact and on releases

GitHub Actions needs to be enabled here: https://github.com/google/lyra/actions. In the mean time an example run can be found here.

Update: Removed the Linux build for now and cleaned up commits. A Linux build will be added in another PR since the specific version requirement makes it a little more complex.

[mchinen]

Thanks! We were meaning to get around to this, so this is very useful. I have some questions and comments.

[EwoutH]

Thanks for your review! I think I implemented or answered all your suggestions and questions, please resolve the conversation if that's done satisfactory.

As of the Linux job, I was indeed looking into installing that specific Clang version. To confirm: the latest stable release (11.1.0) won't cut it and llvm/llvm-project@96ef4f3 is needed specifically?

[mchinen]

As of the Linux job, I was indeed looking into installing that specific Clang version. To confirm: the latest stable release (11.1.0) won't cut it and llvm/llvm-project@96ef4f3 is needed specifically?

Oh, wow, thanks for looking into that.
Yes, using that specific SHA would be ideal.

[EwoutH]

I think this PR is ready, please tell me if you would like any cleanup done. I can squash them to one commit (losing history however), you can also squash them when merging.

Edit: Also, don't forget to enable GitHub actions here: https://github.com/google/lyra/actions

[mchinen]

Looks good, thanks for the changes!

[mchinen]

Looks good, thanks for the changes!