add release-please setup to CI

## Describe the problem

There is no CD script available

## Describe the solution

See recommendations [here](https://www.reddit.com/r/neovim/comments/103d9on/releases_docs_tests_for_plugins/?utm_source=share&utm_medium=ios_app&utm_name=iossmf)

There's even a GitHub action for it: https://github.com/google-github-actions/release-please-action