Add release guidelines

Author: fayazkhan

RELEASING.rst

@@ -0,0 +1,17 @@
+Releasing
+=========
+
+1. Merge all intended and verified pull requests into the ``master`` branch.
+2. Create a local build and test:
+    - Run ``python -m build`` to create a source distribution and a wheel.
+    - Install both artifacts in a fresh virtual environment to ensure they work correctly.
+3. Bump the version number in ``setup.py``. (May be included in the pull request.)
+4. Update the changelog in ``CHANGES.rst``.
+5. Update the release date in ``CHANGES.rst``.
+6. Ensure the latest build passes on GitHub Actions.
+7. Rebuild the documentation and check that it looks correct.
+8. Create a new release on GitHub:
+   - Use the version number as the tag.
+   - Include the changelog in the release notes.
+9. Ensure the release is published.
+10. Test the release by installing it in a fresh virtual environment.