correct drone.yml

.drone.yml

@@ -7,15 +7,15 @@ platform:
     arch: amd64
 
 steps:
-- name: greeting
+    name: greeting
     commands:
     - echo hello world
-- name: build
+    name: build
     commands:
     - docker build -t docker-php-nginx .
 
 trigger:
-event:
-- push
-- tag
-- rollback
+    event:
+    - push
+    - tag
+    - rollback