Update .gitlab-ci.yml

2 jobs for master
Status Job ID Name Coverage
  Test
failed #91
pages
build

00:03:45

canceled #90
pages
build

 
Name Stage Failure
failed
build Test There is an unknown failure, please try again
No pages of output.
Transcript written on main.log.
Latexmk: Log file says no output from latex
Latexmk: For rule 'pdflatex', no output was made
Failure to make 'main.pdf'
Collected error summary (may duplicate other messages):
pdflatex: Command for 'pdflatex' gave return code 256
Latexmk: Errors, in force_mode: so I tried finishing targets
ERROR: Job failed: exit code 1