Update pica-dokuwiki/docker-compose.yml

pica-dokuwiki/docker-compose.yml

 version : "2.4"
 
+volumes:
+  dokuwiki-app-volume:
+    external: 
+        name: "docker_dokuwiki"
+
 networks:
   docker_default:
     external: true
@@ -9,7 +14,7 @@ services:
         image: pica-dokuwiki:stable
         container_name: dokuwiki-app
         volumes:
-          - /DATA/docker/wiki/html:/var/www/html
+          - dokuwiki-app-volume:/var/www/html
         security_opt:
           - no-new-privileges
         mem_limit: "2048m"