Docs/add contributing link

[rolandjitsu]

What kind of change does this PR introduce?

• [ ] Bug Fix
• [ ] Feature
• [ ] Refactoring
• [ ] Style
• [ ] Build
• [ ] Chore
• [x] Documentation
• [ ] CI

Did you add tests for your changes?

• [ ] Yes, my code is well tested
• [x] Not relevant

If relevant, did you update the documentation?

• [x] Yes, I've updated the documentation
• [ ] Not relevant

Summary

Updated badges and add contributing link.

Does this PR introduce a breaking change?

No.

Other information

[github-actions[bot]]

:tada: This PR is included in version 2.2.3 :tada:

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot :package::rocket: