Update .gitlab-ci.yml

2 jobs for thoennes-master-patch-64591 in 1 minute and 20 seconds
Name Stage Failure
build Build

Skipping Git submodules setup
Executing "step_script" stage of the job script
$ mkdir build
$ cd build
$ cmake ..
CMake Error: The source directory "/builds/thoennes/cpptests" does not appear to contain CMakeLists.txt.
Specify --help for usage, or press the help button on the CMake GUI.
ERROR: Job failed: exit code 1