gitlab-ci: Don't use trigger: to trigger head.hackage builds
Due to head.hackage#68 (closed)
we cannot use trigger:
without granting all users push privileges
to ghc/head.hackage>'s master
branch.
Due to head.hackage#68 (closed)
we cannot use trigger:
without granting all users push privileges
to ghc/head.hackage>'s master
branch.