Update CONTRIBUTING.md

Author: CodeWithSushil

.github/CONTRIBUTING.md

@@ -1 +1,21 @@
-## Contribute
+# Contributing
+
+Thanks for contributing!
+
+## Requirements
+
+- PHP 8.2+
+- Composer
+- PSR-12 Code Style
+
+## How to Contribute
+
+1. Fork & create a branch: `feature/my-feature`
+2. Add tests and changelog if needed
+3. Open a PR and link changelog issue: `#123`
+
+## Checklist
+
+- [ ] Code follows style
+- [ ] CI (PHPStan, PHPUnit) passes
+- [ ] Changelog submitted