Update .gitlab-ci.yml file

  after_script:                                                                          

    - git config --global user.email "davide.ricci@inaf.it"                              

    - git config --global user.name "CI Bot"                                             

    - git checkout -b validated                                                          

    - git checkout validated                                                          

    - git add .                                                                          

    - MAIN_COMMIT_MSG=$(git log -1 --pretty=%B $CI_COMMIT_SHA)                           

    - |