docs: update documentation about releases

Author: iMichka

docs/releasing.rst

@@ -1,14 +1,36 @@
 Releasing
 =========
 
+Preparation
+-----------
+
+Run `git checkout develop`.
+
 To build a new release, modify the version number in:
 
 ``pygccxml/__init__.py``
 
 This version number will then automatically be used to build
 the documentation and by the setup.py script when building the wheels.
 
-Do not forget to document the changes in the ``CHANGELOG.md`` file.
+Run `git add . && git commit -m "Bump version major.minor.minor"`.
+
+Do not forget to document the latest changes in the ``CHANGELOG.md`` file.
+
+Merging and releasing
+---------------------
+
+Merge develop into master:
+
+Run `git merge develop master`.
+
+Tag the version (do not forget the v):
+
+Run `git tag vmajor.minor.minor`.
+
+Run `git push origin v2.0.0 && git push origin master`
+
+Wait for the CI checks to run before uploading the release to pypi.
 
 Uploading to pypi
 -----------------