Update .gitlab-ci.yml

1 job for master in 14 seconds
Status Job ID Name Coverage
  Test
failed #98
pages
build

00:00:14

 
Name Stage Failure
failed
build Test There is an unknown failure, please try again
l.1 \documentclass
{beamer}
?
! Emergency stop.
l.1 \documentclass
{beamer}
! ==> Fatal error occurred, no output PDF file produced!
Transcript written on main.log.
ERROR: Job failed: exit code 1