chore: use GitHub Action

[ldez]

Replace Travis with GitHub Action.

[mibk]

Thank you for your contributions, but I'm not sure I can merge this as is.

• “chore: update Go version” seems fine as it is. I'd be happy to merge this.
• “chore: add .gitignore” appears unnecessary. The .idea directory can be added to the global .gitignore file instead.
• “chore: use GitHub Actions” I don't have experience with GitHub Actions, and this seems a bit too complex for a tool that's essentially in maintenance mode. Including a Makefile is not necessary at all.

[ldez]

“chore: use GitHub Actions” I don't have experience with GitHub Actions, and this seems a bit too complex for a tool that's essentially in maintenance mode. Including a Makefile is not necessary at all.

Currently, you are using Travis but Travis is dead, which means you have no CI.
Even if the project is in maintenance mode, I think a CI is always useful.

The Makefile is just a way to document the project.