reference docker/moby issue reporting unexpected tmpfs ownership/mode after restarting container

https://github.com/moby/moby/issues/20437

tasks/main.yml

@@ -13,6 +13,8 @@
     - type: tmpfs
       target: /home/dump/.ssh # authorized_keys
       tmpfs_size: 16k
+      # > Fails in subsequent container starts.
+      # https://github.com/moby/moby/issues/20437
       tmpfs_mode: '1777'
     networks: [name: '{{ mysqldump_sshd_network_name }}']
     purge_networks: yes