DOC: Added CITATION.cff to the list of files in the release guide where the...

DOC: Added CITATION.cff to the list of files in the release guide where the version number must be updated

RELEASE_GUIDELINES.md

@@ -17,8 +17,10 @@ guidelines of the CaosDB Project
 
 2. Check all general prerequisites.
 
-3. Update `src/doc/conf.py` version and check that the correct caosdb-server
-   version is listed in `DEPENDENCIES.md`.
+3. Update the version:
+   - Update `src/doc/conf.py` version and check that the correct caosdb-server
+     version is listed in `DEPENDENCIES.md`.
+   - `CITATION.cff` (update version and date)
 
 4. Merge the release branch into the main branch.