Update .gitlab-ci.yml

1 job for master in 12 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #95
pages
build

00:00:12

 
Name Stage Failure
failed
build Test There is an unknown failure, please try again
/usr/bin/tlmgr: Initialization failed (in setup_unix_one):
/usr/bin/tlmgr: could not find a usable xzdec.
/usr/bin/tlmgr: Please install xzdec and try again.
tlmgr: Couldn't set up the necessary programs.
Installation of packages is not supported.
Please report to texlive@tug.org.
Use of uninitialized value $r in split at /usr/bin/tlmgr line 3899.
tlmgr: Cannot find main repository, you have to tag one as main!
ERROR: Job failed: exit code 1