Port basics of .travis.yml to GitHub Actions

[Enselic]

"master doc to gh-pages" has not been ported yet for example, but having the
basics work will certainly be better than having nothing.

[Enselic]

Example run: https://github.com/Enselic/pkg-config-rs/pull/1/checks

Fails on Rust 1.30 because of #123 (comment), but I'm not sure if you want to fix the code or bump MSRV, so I just left it as this for now.

[Enselic]

I see here now that you prefer to change the code over bumping MSRV, so I will leave it at Rust 1.30.

[sdroege]

"master doc to gh-pages" has not been ported yet for example

That also seems rather unnecessary at this point as the docs are on docs.rs anyway :)

but having the > basics work will certainly be better than having nothing.

As Travis is completely broken, can you also remove the .travis.yml here? It's not useful anyway. And change the "build" badge in the README.md to the corresponding one from the GitHub Actions?

Seems all good to me otherwise, thanks a lot!

[Enselic]

As Travis is completely broken, can you also remove the .travis.yml here? It's not useful anyway. And change the "build" badge in the README.md to the corresponding one from the GitHub Actions?

Done and done. (You can confirm the badge URL is correct by replacing "rust-lang" with "Enselic" to get the badge of my fork: https://github.com/Enselic/pkg-config-rs/actions/workflows/ci.yml/badge.svg)

Happy to help!

[sdroege]

Thanks! I'll upload a new release to crates.io with the 1.30 fix later.