.gitlab-ci.yml: Fix typo

4 jobs for dev in 51 seconds (queued for 2 seconds)
Name Stage Failure
test_browser_unit Test Unit There is an unknown failure, please try again
ok 567 - reverse of the previous

Makefile:21: recipe for target 'nightmare' failed
make[1]: *** [nightmare] Error 1
make[1]: Leaving directory '/home/gitlab-runner/builds/b8d876c1/0/vidjil/vidjil/browser/test'
Makefile:36: recipe for target 'unit_browser' failed
make: *** [unit_browser] Error 2
ERROR: Job failed: exit status 1