chore: add pull request template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,20 @@
+> [!WARNING]
+> Although this software is open source and we welcome contributions, we believe these contributions should be preceded by an open discussion.
+> Open discussions tend to result in better solutions to any given problem, and help maintain and improve the quality of the software.
+> If you would like to see a bug fixed or a new feature implemented, please open an issue for the discussion rather than directly opening a pull request.
+
+> [!IMPORTANT]
+> Please make sure to check our [Contributing Guidelines](https://github.com/cartesi/rollups-node/blob/main/docs/contributing.md) and, most importantly, review our [Contributing License Agreement](https://forms.gle/k3E9ZNkZY6Vy3mkK9), sign and send it to [[email protected]](mailto:[email protected]) before we can proceed.
+
+When you finally create a pull request, please follow these guidelines:
+
+- Make sure the description clearly describes the problem, its solution, and references the associated issue;
+- Do not create large pull requests (involving many different changes) because these are difficult to review.
+Instead, break large changes into smaller ones and create independent pull requests for each one;
+- Use different pull requests for different issues. Each pull request should address a single issue;
+- When fixing a bug or adding a new feature, make sure to add tests that cover your changes.
+This will ensure the changes will continue to work in the future;
+- Verify that changes do not break the tests. You can check this with `make test`;
+- Follow the same coding style rules as the rest of the code base;
+- Pull requests for stylistic changes (or even simple typos or grammatical errors) may be rejected.
+Pull requests should always address worthy issues.