message: docs: fix wrong link in CONTRIBUTING.md
  The link to the CONTRIBUTING.md file was not correct
diff: Please see [Using git with Angular repositories](https://docs.google.com/document/d/1h8nijFSaa1jG_UE8v4WP7glh5qOUXnYtAtJh_gwOQHI/edit)
  for details about how we maintain a linear commit history, and the rules for committing.
  -As a contributor, just read the instructions in [CONTRIBUTING.md](CONTRIBUTING.md) and send a pull request.
  +As a contributor, just read the instructions in [CONTRIBUTING.md](../CONTRIBUTING.md) and send a pull request.
  Someone with committer access will do the rest.
  # Change approvals
  