Update rsnapshot for updated container interface

A linuxserver/rsnapshot image update without tag update broke compatibility.

docker-compose.rsnapshot.yml

@@ -4,10 +4,6 @@ services:
     image: linuxserver/rsnapshot:1.4.5
     restart: unless-stopped
     volumes:
-    - /opt/rsnapshot/etc:/etc/rsnapshot
+    - /opt/rsnapshot:/config
-    - /opt/rsnapshot/var/log:/var/log
-    - /opt/rsnapshot/var/run:/var/run
-    - /opt/rsnapshot/var/spool:/var/spool
-    - /opt/rsnapshot/usr:/host/usr
     - /media/jupiter/rsnapshot:/host/scratch
-    - /root/.ssh:/root/.ssh
+    - /root/.ssh:/root/.ssh:ro