audit: Use version pinned by brew while executing rubocop cli

Library/Homebrew/cmd/style.rb

@@ -119,10 +119,10 @@ module Homebrew
     when :print
       args << "--display-cop-names" if ARGV.include? "--display-cop-names"
       args << "--format" << "simple" if files
-      system(cache_env, "rubocop", *args)
+      system(cache_env, "rubocop", "_#{HOMEBREW_RUBOCOP_VERSION}_", *args)
       !$CHILD_STATUS.success?
     when :json
-      json, _, status = Open3.capture3(cache_env, "rubocop", "--format", "json", *args)
+      json, _, status = Open3.capture3(cache_env, "rubocop", "_#{HOMEBREW_RUBOCOP_VERSION}_", "--format", "json", *args)
       # exit status of 1 just means violations were found; other numbers mean
       # execution errors.
       # exitstatus can also be nil if RuboCop process crashes, e.g. due to