Updated CONTRIBUTION.MD

[diestrin]

Proposed changes

New changes and content about how to contribute to Convector

Checklist

• [x] I have read the CONTRIBUTING doc
• [x] Lint and unit tests pass locally with my changes
• [x] All the commits have been squashed into a single commit following the conventional commits guide
• [x] All the commits are signed with git sign-off
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added necessary documentation (if appropriate)