fix drone tag var

.drone.yml

@@ -33,7 +33,7 @@ steps:
     password:
       from_secret: docker_password
     repo: takaoni/tenkan
-    tags: ${'DRONE_COMMIT_SHA':0:8}
+    tags: ["${DRONE_COMMIT_SHA:0:7}", "latest"]
     dockerfile: docker/Dockerfile
   when:
     branch:
@@ -49,7 +49,7 @@ steps:
     kubernetes_token:
       from_secret: kube_token
   commands:
-    - kubectl set image deployment/tenkan fqserv=takaoni/tenkan:${'DRONE_COMMIT_SHA':0:8} -n gemini
+    - kubectl set image deployment/tenkan fqserv=takaoni/tenkan:"${DRONE_COMMIT_SHA:0:8}" -n gemini
   when:
     branch:
     - master