Merge branch 'bvl-add-galician' into 'master'

Add Galician as an available language

Closes #43227

See merge request gitlab-org/gitlab-ce!21202

changelogs/unreleased/bvl-add-galician.yml

+---
+title: Add Galician as an available language.
+merge_request: 21202
+author:
+type: added

lib/gitlab/i18n.rb

@@ -5,6 +5,7 @@ module Gitlab
     AVAILABLE_LANGUAGES = {
       'en' => 'English',
       'es' => 'Español',
+      'gl_ES' => 'Galego',
       'de' => 'Deutsch',
       'fr' => 'Français',
       'pt_BR' => 'Português (Brasil)',