Install latest containerd 1.6.x (#1247)

Author: cartermckinnon

eks-worker-al2-variables.json

@@ -13,7 +13,7 @@
     "binary_bucket_region": "us-west-2",
     "cache_container_images": "false",    
     "cni_plugin_version": "v0.8.6",
-    "containerd_version": "1.6.6-1.amzn2.0.2",
+    "containerd_version": "1.6.*",
     "creator": "{{env `USER`}}",
     "docker_version": "20.10.17-1.amzn2.0.1",
     "encrypted": "false",