docs: add PR Template and CONTRIBUTING.md

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,6 @@
+### Pull Request Checklist
+
+<!-- Make sure to read and accept the CLA, before you open the pull request! -->
+<!-- Tick the checkbox below if you accept our CLA (`[x]`) -->
+
+- [ ] I have read and accept the [Contributor License Agreement](https://opensource.porsche.com/docs/cla)

CONTRIBUTING.md

@@ -0,0 +1,49 @@
+# Contributing to the Cookie Consent Banner
+
+Thanks for your interest in contributing to this project! :thumbsup: :thumbsup:
+
+## Reporting an Issue
+
+Found an issue with the script or have an idea how to improve?
+
+1. Check if your issue or idea has already been reported: [See Issues](https://github.com/porscheofficial/vercel-static-extensions/issues)
+2. Create an issue, but don't forget to provide a test case or even a live example: [Create Issue](https://github.com/porscheofficial/vercel-static-extensions/issues/new)
+
+## Submitting a Pull Request
+
+Want to contribute to the project? That's awesome! :tada:
+
+1. Let's start with a [fork of the project](https://github.com/porscheofficial/vercel-static-extensions/fork)
+
+2. Clone your fork:
+
+```sh
+git clone [CLONE URL PROVIDED BY GITHUB]
+```
+
+3. Create a new branch:
+
+```sh
+git checkout -b feature/short-description
+```
+
+4. Check if all tests pass:
+
+```sh
+`yarn test:ci
+```
+
+5. Push your branch to your fork:
+
+```sh
+git push origin feature/short-description
+```
+
+6. Open a Pull Request
+
+and [create a branch](https://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging) for your feature or fix.
+
+Just make sure that:
+
+- Your pull request is focused and you avoid unrelated commits
+- You read and accept our [Contributor License Agreement](https://opensource.porsche.com/docs/cla)