feat: github action to upload docker image to artifact registry

[d0choa]

✨ Context

It would be handy to have a gentropy image of the dev branch available in GCP at all times.

🛠 What does this PR implement

This GitHub Action aims to build the image of gentropy from the Dockerfile and upload it to the GCP Artefact Registry.

🙈 Missing

• I can't make sure the action runs properly locally. It's using the secrets in GitHub. It's unlikely to work in the first shot
• It only deploys the dev branch for now. We could have docker images for each release as well if this works.

🚦 Before submitting

• Do these changes cover one single feature (one change at a time)?
• Did you read the contributor guideline?
• Did you make sure to update the documentation with your changes?
• Did you make sure there is no commented out code in this PR?
• Did you follow conventional commits standards in PR title and commit messages?
• Did you make sure the branch is up-to-date with the dev branch?
• Did you write any new necessary tests?
• Did you make sure the changes pass local tests (make test)?
• Did you make sure the changes pass pre-commit rules (e.g poetry run pre-commit run --all-files)?

[ireneisdoomed]

Let's see if it works!