[dev] Add Github Actions for package releasing

[amureki]

Adds an automated action based on GitHub releases to simplify PyPI release process.

[amureki]

@berinhard hey Bernardo! Would you mind checking this one and adding secrets in repo settings, if this is okay with you?

For example, after we merge this and set up secrets, possible next steps for the release would be:

• Update version in model_bakery/__about__.py and docs/source/conf.py
• Update CHANGELOG.md with the new version data
• Draft new release via https://github.com/model-bakers/model_bakery/releases against latest main branch

This will trigger a GitHub Action to publish a new release in PyPI.

[berinhard]

hey @amureki this looks great! it opens path to any collaborator to release new versions, not just me.

would you or @anapaulagomes be comfortable with that? IMHO, this PR makes the deploy process more solid than it's now and less riskier. we could create a model-bakers user in pypi as well, right? so our personal pypi keys won't be needed. what do you think?