👥(github) update pull request template

We added a new section to the pull request
template to ensure that contributors
follow the correct process for submitting
pull requests.

Author: AntoLC

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,11 +1,22 @@
 ## Purpose
 
-Description...
+Describe the purpose of this pull request. 
 
 
 ## Proposal
 
-Description...
+- [ ] item 1...
+- [ ] item 2...
 
-- [] item 1...
-- [] item 2...
+## External contributions
+
+Thank you for your contribution! 🎉  
+
+Please ensure the following items are checked before submitting your pull request:
+- [ ] I have read and followed the [contributing guidelines](https://github.com/suitenumerique/docs/blob/main/CONTRIBUTING.md)
+- [ ] I have read and agreed to the [Code of Conduct](https://github.com/suitenumerique/docs/blob/main/CODE_OF_CONDUCT.md)
+- [ ] I have signed off my commits with `git commit --signoff` (DCO compliance)
+- [ ] I have signed my commits with my SSH or GPG key (`git commit -S`)
+- [ ] My commit messages follow the required format: `<gitmoji>(type) title description`
+- [ ] I have added a changelog entry under `## [Unreleased]` section (if noticeable change)
+- [ ] I have added corresponding tests for new features or bug fixes (if applicable)