feat(ci): add automatic releases and publish to luarocks

[NTBBloodbath]

Hey, hope you guys are doing well!

It seems like telescope.nvim is already there and it would be great to have their extensions available too :)

Summary

This PR is part of a push to get Neovim plugins on LuaRocks.

• See this blog post, which follows up on a series of posts.
• See also: rocks.nvim, a new luarocks-based plugin manager.

Things done:

• Add a release-please workflow that creates release PRs with SemVer versioning based on conventional commits.
• Add a workflow that publishes tags to LuaRocks when a tag is pushed.

The workflows are based on this guide by @vhyrro.

Notes

• On each merge to master, the release workflow creates (or updates an existing) release PR.
• You decide when to merge release PRs. Doing so will result in a SemVer tag, and a GitHub release, which will trigger the luarocks workflow.
• For the luarocks workflow to work, someone with a luarocks.org account will have to add their API key to this repo's GitHub actions secrets, as mentioned in the guide mentioned above.

[jamestrew]

Thanks for the PR and info.
I've been meaning to start versioning telescope-file-browser properly for a while. I have a few things I want to take care of before cutting a 1.0.0 release. I will come back to this PR when that's ready.