Documented example requires recreate of the volume

[janevert]

I found out that the full example at the bottom of the readme causes the volume to be recreated each time because:

ERROR: Configuration for volume test-fs specifies driver cephfs, but a volume with the same name uses a different driver (cephfs:latest). If you wish to use the new configuration, please remove the existing volume "test-ceph-integration_test-fs" first:

Using driver: cephfs:latest fixes the issue for me and allows to start and stop the container without recreating the volume.