Enable even more frozen string for lib/gitlab

Enables frozen string for the following:

* lib/gitlab/hook_data/**/*.rb
* lib/gitlab/i18n/**/*.rb
* lib/gitlab/import/**/*.rb
* lib/gitlab/import_export/**/*.rb
* lib/gitlab/kubernetes/**/*.rb
* lib/gitlab/legacy_github_import/**/*.rb
* lib/gitlab/manifest_import/**/*.rb
* lib/gitlab/metrics/**/*.rb
* lib/gitlab/middleware/**/*.rb

Partially addresses gitlab-org/gitlab-ce#47424.

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/gitlab/metrics/web_transaction.rb b/lib/gitlab/metrics/web_transaction.rb
index 723ca576aab..b2a43d46fb2 100644
--- a/lib/gitlab/metrics/web_transaction.rb
+++ b/lib/gitlab/metrics/web_transaction.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Gitlab
   module Metrics
     class WebTransaction < Transaction
@@ -40,7 +42,7 @@ module Gitlab
         # increasing the cardinality of our metrics, we limit the number of
         # possible suffixes.
         if suffix && ALLOWED_SUFFIXES.include?(suffix)
-          action += ".#{suffix}"
+          action = "#{action}.#{suffix}"
         end
 
         { controller: controller.class.name, action: action }