Update .gitlab-ci.yml

1 job for develop in 51 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
failed #22658
build

00:00:51

 
Name Stage Failure
failed
build Build
Done in 0.67s.

CI:SASS build error: Error: Command failed: grunt default

Done in 27.39s.
$ grunt default
/bin/bash: line 106: grunt: command not found
Cleaning up file based variables
ERROR: Job failed: exit code 1