Use older format for drone

.drone.yml

@@ -1,13 +1,7 @@
-kind: pipeline
-name: testing
 
-clone:
+pipeline:
-  depth: 50
+  testing:
-
-steps:
-  - name: testing
     image: golang:1.11
-    pull: true
     commands:
       - go test -v .
       - go vet