Update .gitlab-ci.yml

1 job for master in 27 seconds (queued for 1 second)
Status Job ID Name Coverage
  Deploy
failed #129805
pages

00:00:27

 
Name Stage Failure
failed
pages Deploy
Skipping Git submodules setup
Restoring cache
Downloading artifacts
Running before_script and script
$ pip install -U sphinx, alabaster
ERROR: Invalid requirement: 'sphinx,'
Running after_script
Uploading artifacts for failed job
ERROR: Job failed: exit code 1