chore: use single universal PR template

GH does not support directly selecting PR template on creation

Author: rudokotrla

.github/pull_request_template.md

@@ -0,0 +1,35 @@
+<!---
+**IMPORTANT**:
+
+Please do not create a Pull Request without creating an issue first.
+A similar PR may already be submitted!
+Please search among the [Pull requests](https://github.com/iamhectorsosa/supabase-modules/pulls) before creating one.
+
+For more information, see the [`CONTRIBUTING`(https://github.com/iamhectorsosa/supabase-modules/blob/main/CONTRIBUTING.md) guide.
+
+-->
+
+## Summary
+
+This PR implements / improves the following **features**:
+
+- Feature 1
+- Feature 2
+
+and fixes following **bugs**:
+
+- Bug 1
+- Bug 2
+
+**Breaking changes:**
+
+- Breaking change 1
+- Breaking change 2
+
+## Testing
+
+Please describe how the changes can be tested
+
+## Related isssues
+
+Put _closes #XXXX_ in your comment to auto-close the issue that your PR implements.