quorum ATs can run on medium executor (#3830)

* quorum ATs may run on medium executor

Signed-off-by: Sally MacFarlane <sally.macfarlane@consensys.net>

.circleci/config.yml

@@ -38,10 +38,10 @@ executors:
     environment:
       GRADLE_OPTS: -Dorg.gradle.daemon=false -Dorg.gradle.parallel=true -Dorg.gradle.workers.max=4
       
-  quorum_ats_executor_xl:
+  quorum_ats_executor_med:
     docker:
       - image: cimg/openjdk:11.0
-    resource_class: xlarge
+    resource_class: medium
     working_directory: ~/project
     environment:
       GRADLE_OPTS: -Dorg.gradle.daemon=false
@@ -279,7 +279,7 @@ jobs:
 
   acceptanceTestsQuorum:
     parallelism: 1
-    executor: quorum_ats_executor_xl
+    executor: quorum_ats_executor_med
     steps:
       - attach_workspace:
           at: ~/project