docs: update pre commit instructions

Author: leafspark

CONTRIBUTING.md

@@ -19,9 +19,11 @@ First off, thanks for taking the time to contribute! 🎉👍
 
 1. Fork the repo
 2. Create your feature branch (`git checkout -b feature/AmazingFeature`)
-3. Commit your changes (`git commit -m 'Add some AmazingFeature'`)
-4. Push to the branch (`git push origin feature/AmazingFeature`)
-5. Open a Pull Request
+3. Install pre-commit: (`pip install pre-commit`)
+4. Set up the git hook scripts: (`pre-commit install`)
+5. Commit your changes (`git commit -m 'Add some AmazingFeature'`)
+6. Push to the branch (`git push origin feature/AmazingFeature`)
+7. Open a Pull Request
 
 ## Styleguides