Update .gitlab-ci.yml

1 job for master in 43 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #623
build

00:00:43

 
Name Stage Failure
failed
build Test
Hit:3 http://cdn-fastly.deb.debian.org/debian stretch-updates InRelease
Hit:4 http://cdn-fastly.deb.debian.org/debian stretch Release
Reading package lists...
$ apt-get install --yes cmake build-essential intel-mkl
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package intel-mkl
ERROR: Job failed: exit code 1