Autocorrect RuboCop violations in danger/**/Dangerfile

danger/changelog/Dangerfile

@@ -2,9 +2,9 @@
 
 require 'yaml'
 
-NO_CHANGELOG_LABELS = %w[backstage QA test]
-SEE_DOC = "See [the documentation](https://docs.gitlab.com/ce/development/changelog.html)."
-MISSING_CHANGELOG_MESSAGE = <<~MSG
+NO_CHANGELOG_LABELS = %w[backstage QA test].freeze
+SEE_DOC = "See [the documentation](https://docs.gitlab.com/ce/development/changelog.html).".freeze
+MISSING_CHANGELOG_MESSAGE = <<~MSG.freeze
 **[CHANGELOG missing](https://docs.gitlab.com/ce/development/changelog.html).**
 
 You can create one with:

danger/changes_size/Dangerfile

-# rubocop:disable Style/SignalException
-
 # FIXME: git.info_for_file raises the following error
 # /usr/local/bundle/gems/git-1.4.0/lib/git/lib.rb:956:in `command':  (Danger::DSLError)
 # [!] Invalid `Dangerfile` file:

danger/database/Dangerfile

 # frozen_string_literal: true
-# rubocop:disable Style/SignalException
 
 # All the files/directories that should be reviewed by the DB team.
 DB_FILES = [

danger/gemfile/Dangerfile

-# rubocop:disable Style/SignalException
-
-GEMFILE_LOCK_NOT_UPDATED_MESSAGE = <<~MSG
+GEMFILE_LOCK_NOT_UPDATED_MESSAGE = <<~MSG.freeze
 **%<gemfile>s was updated but %<gemfile_lock>s wasn't updated.**
 
 Usually, when %<gemfile>s is updated, you should run

danger/specs/Dangerfile

-# rubocop:disable Style/SignalException
-
-NO_NEW_SPEC_MESSAGE = <<~MSG
+NO_NEW_SPEC_MESSAGE = <<~MSG.freeze
 You've made some app changes, but didn't add any tests.
 That's OK as long as you're refactoring existing code,
 but please consider adding the ~backstage label in that case.