CI: pre-commit hook integration

CONTRIBUTING.md

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+# Information for Contributors
+
+Contributions in the form of pull requests, issue reports, and feature requests are welcome!
+
+## Submitting a PR
+
+- [ ] Fork the [esp-protocols repository on GitHub](https://github.com/espressif/esp-protocols) to start making your changes.
+
+- [ ] Install pre-commit hooks: `pip install pre-commit && pre-commit install`
+
+- [ ] Send a pull request (PR) and work with us until it gets merged and published. Contributions may need some modifications, so a few rounds of review and fixing may be necessary.
+
+For quick merging, the contribution should be short, and concentrated on a single feature or topic. The larger the contribution is, the longer it would take to review it and merge it.