Maintenance: Update dependency graphql to v2.0.18

Gemfile.lock

@@ -213,7 +213,7 @@ GEM
       activesupport (>= 5.0)
     gmail_xoauth (0.4.2)
       oauth (>= 0.3.6)
-    graphql (2.0.17)
+    graphql (2.0.18)
     graphql-batch (0.5.2)
       graphql (>= 1.10, < 3)
       promise.rb (~> 0.7.2)

spec/graphql/gql/record_loader_spec.rb

@@ -144,7 +144,7 @@ RSpec.describe Gql::RecordLoader, type: :graphql do
           'Group Load'             => 11,
           'UserGroup Exists?'      => 20,
           'Ticket Load'            => 1,
-          'Ticket Exists?'         => 1,
+          # 'Ticket Exists?'         => 1,
           'User Load'              => 2,
           'Organization Load'      => 1,
           'Ticket::State Load'     => 1,
@@ -162,7 +162,7 @@ RSpec.describe Gql::RecordLoader, type: :graphql do
           'Group Load'             => 3,
           'UserGroup Exists?'      => 2,
           'Ticket Load'            => 1,
-          'Ticket Exists?'         => 1,
+          # 'Ticket Exists?'         => 1,
           'User Load'              => 2,
           'Organization Load'      => 1,
           'Ticket::State Load'     => 1,