Update gitlab_git to 7.0.0.rc11
Run 'GC.start' after every EmailsOnPushWorker job
Merge branch 'update-gitlab-git' into 'master'

Update gitlab_git to 7.0.0.rc11

See merge request !1256
Merge branch 'sidekiq_gc_start' into 'master'

Run 'GC.start' after every EmailsOnPushWorker job

This change removed a lot of large peaks of the Sidekiq memory growth graph on gitlab.com.

See merge request !1257