update drone

.drone.yml

@@ -5,6 +5,9 @@ name: default
 steps:
   - name: package
     image: maven:3-jdk-10
+    volumes:
+      - name: maven-dir
+        path: /root/.m2/repository
     commands:
       - mvn clean package -Dmaven.skip.test=true
     when:
@@ -26,6 +29,9 @@ volumes:
   - name: wars-dir
     host:
       path: /home/ww/wars
+  - name: maven-dir
+    host:
+      path: /home/ww/m2/repository
 
 trigger:
   branch: