update_ci_reference_files: improve update instructions
Improve the instructions on how to fetch
and update the developer branch without having to add a new remote.
Example:
The next step is to update the MR with the new content i.e. the References.py file and the digest files.
IMPORTANT: before you do this, you must first make sure that the local repository is on same branch as the MR by doing:
$ git fetch --no-tags https://:@gitlab.cern.ch:8443/llewitt/athena.git UseSimilarityInGsfMeasurementUpdator:mr-71698
$ git switch mr-71698
$ git rebase upstream/main
cc @atlas-release-coordinators
Edited by Frank Winklmeier