Implement Continuous Integration Using GitHub Actions

[dylanmtaylor]

This pull request leverages GitHub Actions to automatically build scrcpy on every commit or pull request.

[dylanmtaylor]

This is ready for review, it seems to work well. Please take a look and let me know what you think.

[rom1v]

Oh, great! Thank you 👍

Is it possible to enable/test it without pushing it on master?

[dylanmtaylor]

It have been doing some testing on my fork here https://github.com/dylanmtaylor/scrcpy/actions

[dylanmtaylor]

I squashed those commits to make it a cleaner merge.

[rom1v]

OK, thank you. 👍

Sorry, I currently don't have much time to work on scrcpy. I'd like to investigate the checkstyle issue too.
I have this PR in my TODO, but I cannot say when I have time to check/merge.

But don't worry, I didn't forget, and I have it in mind 😉

[Biswa96]

Just asking. Is it necessary to use docker container to build the project? As far as I have seen, installing packages in GHA does not take too much time.

[dylanmtaylor]

Docker makes the build more reproducible, and you can run in the same container locally as on the CI system, where you cannot easily reproduce the GitHub actions virtual machine.