update drone test script

.drone.yml

@@ -4,9 +4,10 @@ type: exec
 name: env_test
 
 steps:
- - name: env_script
+- name: env_script
-   commands:
+  commands:
-    - /usr/local/bin/env.sh
+  - /usr/local/bin/env.sh
-   when:
-     event: pull
 
+trigger:
+  event:
+  - pull_request