Merge branch 'update-author-prefix-on-merge-request-notification' into 'master'

Update author prefix on merge request notification

See merge request gitlab-org/gitlab-ce!31057

app/views/notify/new_merge_request_email.html.haml

@@ -5,7 +5,7 @@
   .branch
     = merge_path_description(@merge_request, 'to')
   .author
-    Author #{@merge_request.author_name}
+    Author: #{@merge_request.author_name}
   .assignee
     = assignees_label(@merge_request)
   .approvers