update drone yaml

.drone.yml

@@ -1,13 +1,15 @@
-pipeline:
- nginx-conf:
+kind: pipeline
+name: default
+steps:
+  - name: nginx-conf
     image: nginx:mainline
     commands: 
      - cp -r nginx /etc/nginx
      - nginx -t
- docker:
+  - name: docker
     image: plugins/docker
     repo: repo.shimun.net/shimun/seafile
-    tag: riffol
+    auto_tag: true
     registry: repo.shimun.net
     storage_path: /drone/.docker
     secrets: ["docker_username", "docker_password"]
@@ -15,3 +17,5 @@ pipeline:
     cache_from: ["repo.shimun.net/shimun/seafile", "repo.shimun.net/shimun/seafile:nginx-deb", "repo.shimun.net/shimun/seafile:alpine"]
     use_cache: true
     pull_image: false
+    when:
+      event: tag