removes version parameter, adds external: true for volumes

docker-compose.yml

       - traefik-logs:/logs
       - traefik-static:/etc/traefik/static:ro
 
-version: "3.4"
-
 volumes:
   cache:
+    external: true
     name: composer-cache
   db:
+    external: true
     name: ${PREFIX}-db
   root:
+    external: true
     name: ${PREFIX}-root
   traefik-certs:
+    external: true
     name: ${PREFIX}-traefik-certs
   traefik-dynamic:
+    external: true
     name: ${PREFIX}-traefik-dynamic
   traefik-logs:
+    external: true
     name: ${PREFIX}-traefik-logs
   traefik-static:
+    external: true
     name: ${PREFIX}-traefik-static
   webroot:
+    external: true
     name: ${PREFIX}-webroot
   wp-cli-cache:
+    external: true
     name: wp-cli-cache