Bump docker builder to 20GB disk

Signed-off-by: DW Talton <dtalton@contractor.linuxfoundation.org>
Change-Id: I669e66d28e9c07f3ada301526c55f2668f0c80c4
diff --git a/jenkins-config/clouds/openstack/cattle/ubuntu1804-docker-4c-4g.cfg b/jenkins-config/clouds/openstack/cattle/ubuntu1804-docker-4c-4g.cfg
index 26cafd4..7108a83 100644
--- a/jenkins-config/clouds/openstack/cattle/ubuntu1804-docker-4c-4g.cfg
+++ b/jenkins-config/clouds/openstack/cattle/ubuntu1804-docker-4c-4g.cfg
@@ -1,4 +1,4 @@
 IMAGE_NAME=ZZCI - Ubuntu 18.04 - docker - x86_64 - 20190927-102054.131
 LABELS=ubuntu1804-docker-4c-4g
 HARDWARE_ID=v2-highcpu-4
-VOLUME_SIZE=10
+VOLUME_SIZE=20