feat: add PR template

.github/pull_request_template.md

@@ -0,0 +1,7 @@
+Thank you for opening a pull request with this project, please also:
+
+* [ ] add a brief description of your changes here
+* [ ] assign a reviewer
+* [ ] start in `draft` mode and `in progress` pipeline in the project (if applicable)
+* [ ] once it's ready put it in the `Review` or `Ready4Merge` pipeline in the project (if applicable) and remove `draft`
+* [ ] if applicable, add this PR to its related issue by one of the special keywords (https://docs.github.com/en/get-started/writing-on-github/working-with-advanced-formatting/using-keywords-in-issues-and-pull-requests#linking-a-pull-request-to-an-issue)