Prefix EmailsOnPush email subject with `[Git]`.

CHANGELOG

@@ -7,6 +7,7 @@ v 7.12.0 (unreleased)
   - Update Asciidoctor gem to version 1.5.2. (Jakub Jirutka)
   - Fix resolving of relative links to repository files in AsciiDoc documents. (Jakub Jirutka)
   - Use the user list from the target project in a merge request (Stan Hu)
+  - Prefix EmailsOnPush email subject with `[Git]`.
 
 v 7.11.2
   - no changes

app/mailers/emails/projects.rb

@@ -93,7 +93,8 @@ module Emails
           "pushed to"
         end
 
-      @subject = "[#{@project.path_with_namespace}]"
+      @subject = "[Git]"
+      @subject << "[#{@project.path_with_namespace}]"
       @subject << "[#{@ref_name}]" if action == :push
       @subject << " "