Update CONTRIBUTING.md to remove CLA step

Removed the step about completing the Contributor License Agreement (CLA) from the contributing guidelines.

Author: danez

CONTRIBUTING.md

@@ -13,16 +13,11 @@ We actively welcome your pull requests.
 3. If you've changed APIs, update the documentation.
 4. Ensure the test suite passes.
 5. Make sure your code lints and typechecks.
-6. If you haven't already, complete the Contributor License Agreement ("CLA").
 
 ## Issues
 We use GitHub issues to track public bugs. Please ensure your description is
 clear and has sufficient instructions to be able to reproduce the issue.
 
-Facebook has a [bounty program](https://www.facebook.com/whitehat/) for the safe
-disclosure of security bugs. In those cases, please go through the process
-outlined on that page and do not file a public issue.
-
 ## License
 react-docgen is [MIT licensed](https://github.com/reactjs/react-docgen/blob/master/LICENSE).