gitlab: added release issue template objectbox#21

Author: dan-obx

.gitlab/issue_templates/release.md

@@ -0,0 +1,14 @@
+**Check-list**
+
+- [ ] Update version in `objectbox/__init__.py`
+- [ ] Check/update dependencies:
+  - [ ] `requirements.txt`: test and increase max. supported versions
+  - [ ] Update the C library version in `download-c-lib.py` and `objectbox/c.py`
+- [ ] Check GitLab CI passes on main branch
+- [ ] Update `README.md`: ensure all info is up-to-date.
+- [ ] Commit and push to GitHub
+- [ ] Clean, run tests and build: `make all`
+- [ ] Publish to PyPI: `make publish`
+  - For this, you will need our login data for https://pypi.org/account/login - it can be found in 1pass
+- [ ] Create a GitHub release
+- [ ] Announce in GitHub issues, create release announcement/blog post.