Replace Travis with GitHub Actions

[abitrolly]

@jiaaro please take a look.

[abitrolly]

@jiaaro what is required to merge this?

[inatuwe]

Hi @jiaaro

Maybe I'm wrong, but I think this Pull Request has to be completed by overriding the travis-ci policy, because it actually replaces it...?

[abitrolly]

@inatuwe what is this travis-ci policy?

[inatuwe]

Hi @abitrolly,

The reason, why this pull request cannot be completed is, that the job "continuous-integration/travis-ci" has not yet succeeded. But the pull request is about removing that job, because travis-ci is no longer supported.

[inatuwe]

@jiaaro, would it be possible for you to bypass the travis-ci policy on this pull request? I think, it's the only way to merge it...