working on same-stage dependencies

prebuild_lab_0:

  stage: lab0

  script:

    - # check that lab0.cpp exists

    - |

      # Check if lab0.cpp exists

      if [ ! -f "lab0.cpp" ]; then

        echo "lab0.cpp does not exist";

        exit 1;

      fi

      # check that lab-1.cpp has been merged (i.e., accepted) into master

      git ls-tree -r origin/master --name-only

      # Check if lab-1.cpp has been merged into master

      git fetch origin master  # Fetch the latest master branch

      if git ls-tree -r origin/master --name-only | grep -q 'lab-1.cpp'; then

        echo "Lab -1 complete";

      else