Remove ununsed autoload entry

gems/gitlab-backup-cli/lib/gitlab/backup/cli/utils.rb

@@ -4,7 +4,6 @@ module Gitlab
   module Backup
     module Cli
       module Utils
-        autoload :MetadataSerialization, 'gitlab/backup/cli/utils/metadata_serialization'
         autoload :PgDump, 'gitlab/backup/cli/utils/pg_dump'
         autoload :Tar, 'gitlab/backup/cli/utils/tar'
       end