release PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,20 @@
+<!-- Still preliminary. -->
+
+When a new release is made for minotaur, the following steps should be taken:
+
+- Update the CHANGELOG.md to include a description of all changes.
+- Add Release date and bump version number to CHANGELOG.md
+- Update the version number in the following files:
+  - [ ] scripts/download_and_localise_package_files.sh
+  - [ ] scripts/ssf_validator.py
+  - [ ] scripts/create_eager_input.sh
+  - [ ] scripts/minotaur_packager.sh
+  - [ ] scripts/validate_downloaded_data.sh
+  - [ ] scripts/run_eager.sh
+  - [ ] scripts/populate_janno.py
+  - [ ] scripts/download_ena_data.py
+- Create new release, release tag, and name.
+
+After the release:
+
+- Update the poseidon-eager release tag used in the [minotaur-recipes repo](https://github.com/poseidon-framework/minotaur-recipes/blob/main/assets/template.config).