ci: enable protection ruleset for main branch

[gvieira18]

Summary

This is a reminder for the future

Branch protection rules for the `main' branch must be enabled. Currently, it is possible to push directly to main without requiring a pull request or passing status checks, which can pose a risk to the stability of the project.

I'm thinking something like this:

• Direct pushes to main are blocked.
• Pull requests are mandatory with at least one approval.
• All required status checks must pass before merging.

If you have any suggestions or counterpoints regarding this change, please feel free to share them so we can discuss and adjust the implementation as needed.

[gvieira18]

Ruleset enabled, if you guys had a problem with the ruleset, ping me on a new issue and we can discuss it.