Implement release workflow as in `miden-debug` repo

[greenhat]

See https://github.com/0xMiden/miden-debug/blob/next/.github/workflows/release.yml

The workflow:

1. The merge from the next to main triggers the release-plz and creates a release PR;
2. When the release PR is merged the git tag is set and artifacts are published under the GH release;
3. The main branch is merged back to the next branch (manual step for now, look into automating it).