Revert "Update maven Docker tag to v3.6 (#238)" (#244)
Revert "Update maven Docker tag to v3.6 (#238)" (#244)

This reverts commit 85fb31233ee4fb70a57a804617494c50181427b3.
GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples,GoogleCloudPlatform/kubernetes-engine-samples