Merge branch 'frozen-string-enable-lib-gitlab-graphql' into 'master'

Enable frozen string for spec/lib/gitlab/graphql

See merge request gitlab-org/gitlab!20593

spec/lib/gitlab/graphql/authorize/authorize_resource_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Graphql::Authorize::AuthorizeResource do

spec/lib/gitlab/graphql/loaders/batch_lfs_oid_loader_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Graphql::Loaders::BatchLfsOidLoader do

spec/lib/gitlab/graphql/loaders/batch_model_loader_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Gitlab::Graphql::Loaders::BatchModelLoader do