add pull request template for releases

.github/PULL_REQUEST_TEMPLATE/pull_request_template.md

@@ -0,0 +1,14 @@
+# Next release
+
+## Description of important changes
+
+... Add here ...
+
+## Checklist for next release
+
+- [ ] finish your development and merge it into the `develop` branch
+- [ ] update documentation
+- [ ] update / fix tests
+- [ ] bump version numbers (in files `aiida_kkr/__init__.py`, `pyproject.toml`, `.bumpversion.cfg`)
+
+If everything is done, you can merge your changes from `develop` back into `master` and create a tag for the new version number. Creating a new tag always  triggers publication to pypi (see `.github/workflows/cd.yml` for the definition of this github action).