[gi-docgen] docs: Add a check list for the release process

[Emmanuele Bassi <ebassi src gnome org>]

commit fa7140e60eae2fed1e4abca3c83803db5a626f6d
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Aug 16 13:57:41 2021 +0100

    docs: Add a check list for the release process
    
    Especially for the Python side, so I don't have to hunt down the part of
    the Python documentation website that contains the packaging tutorial
    every single time:
    
    https://packaging.python.org/tutorials/packaging-projects/

 docs/RELEASING.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
---
diff --git a/docs/RELEASING.md b/docs/RELEASING.md
new file mode 100644
index 0000000..478ac1b
--- /dev/null
+++ b/docs/RELEASING.md
@@ -0,0 +1,15 @@
+Release check list
+==================
+
+- [ ] Collect all changes since the previous tag
+- [ ] Tag the release, using `git tag -s YYYY.N`
+- [ ] Write down all the noteworthy changes in the tag message
+- [ ] Update `twine`: `pip install --upgrade --user twine`
+- [ ] Build a Python dist: `python -m build`
+- [ ] Upload the dist to PyPI: `python -m twine upload dist/*`
+- [ ] Build a Meson dist: `meson setup _build . && meson dist -C _build`
+- [ ] Upload the Meson dist to gnome.org
+- [ ] Clean up the repository: `git clean -xdf`
+- [ ] Bump the version in `meson.build` and `gidocgen/core.py` to `YYYY.N+1`
+- [ ] Push the changes to the repository: `git push origin HEAD`
+- [ ] Push the release tag to the repository: `git push origin YYYY.N`