Fix RABBITMQ_IMAGE reference in aws peer discovery workflow

(cherry picked from commit 22f5f59)

Author: HoloRin

.github/workflows/rabbitmq_peer_discovery_aws.yaml

@@ -67,6 +67,6 @@ jobs:
           --build_tests_only \
           --test_env AWS_ACCESS_KEY_ID=${{ secrets.CONCOURSE_AWS_ACCESS_KEY_ID }} \
           --test_env AWS_SECRET_ACCESS_KEY=${{ secrets.CONCOURSE_AWS_SECRET_ACCESS_KEY }} \
-          --test_env RABBITMQ_IMAGE="pivotalrabbitmq/rabbitmq:${{ github.sha }}" \
+          --test_env RABBITMQ_IMAGE="pivotalrabbitmq/rabbitmq:${{ github.sha }}-otp-max" \
           --test_env AWS_ECS_CLUSTER_NAME="rabbitmq-peer-discovery-aws-actions-${branch_or_tag//./-}" \
           --verbose_failures