Merge branch 'update-command-to-process-po-files' into 'master'

Use the new `gettext:compile` script to process PO files

See merge request !1666

config/software/gitlab-rails.rb

@@ -122,8 +122,8 @@ build do
   command 'yarn install --pure-lockfile --production'
   bundle 'exec rake gitlab:assets:compile', env: assets_compile_env
 
-  # process PO files and generate MO files
-  bundle 'exec rake gettext:pack', env: assets_compile_env
+  # process PO files and generate MO and JSON files
+  bundle 'exec rake gettext:compile', env: assets_compile_env
 
   # Tear down now that gitlab:assets:compile is done.
   delete 'node_modules'