replace `has_matching_label` with `has_matching_label?`

.rubocop_todo.yml

@@ -244,8 +244,11 @@ Style/PerlBackrefs:
 # NameWhitelist: is_a?
 Style/PredicateName:
   Enabled: true
+  Exclude:
+    - 'features/*'
   # NamePrefix: is_
   NamePrefixBlacklist: is_
+  NameWhitelist: has_n_stars
 
 # Offense count: 58
 # Cop supports --auto-correct.

lib/gitlab/prometheus/queries/matched_metrics_query.rb

@@ -42,13 +42,13 @@ module Gitlab
 
           lookup = series.each_slice(MAX_QUERY_ITEMS).flat_map do |batched_series|
             client_series(*batched_series, start: timeframe_start, stop: timeframe_end)
-              .select(&method(:has_matching_label))
+              .select(&method(:has_matching_label?))
               .map { |series_info| [series_info['__name__'], true] }
           end
           lookup.to_h
         end
 
-        def has_matching_label(series_info)
+        def has_matching_label?(series_info)
           series_info.key?('environment')
         end