DOC: Release guidelines now also mention version in src/doc/conf.py

RELEASE_GUIDELINES.md

@@ -20,9 +20,10 @@ guidelines of the CaosDB Project
 
 3. Check all general prerequisites.
 
-4. Prepare [setup.py](./setup.py): Check the `MAJOR`, `MINOR`, `MICRO`, `PRE`
-   variables and set `ISRELEASED` to `True`. Use the possibility to issue
-   pre-release versions for testing.
+4. Update the version:
+   - `version` variables in `src/doc/conf.py`
+   - Version on [setup.py](./setup.py): Check the `MAJOR`, `MINOR`, `MICRO`, `PRE` variables and set
+     `ISRELEASED` to `True`. Use the possibility to issue pre-release versions for testing.
 
 5. Merge the release branch into the main branch.