Update syntax for Drone 0.5

.drone.yml

@@ -1,33 +1,28 @@
-build:
-  image: golang:1.5
+workspace:
+  base: /go
+  path: src/github.com/drone-plugins/drone-terraform
+
+pipeline:
+  test:
+    image: golang:1.6
     environment:
       - CGO_ENABLED=0
     commands:
-    - make deps
-    - make vet
-    - make build
-    - make test
+      - go test -cover -coverprofile=coverage.out
+      - go build -ldflags "-s -w -X main.build=$DRONE_BUILD_NUMBER" -a
 
-publish:
   coverage:
+    image: coverage
     when:
       branch: master
-  docker:
-    username: $$DOCKER_USER
-    password: $$DOCKER_PASS
-    email: $$DOCKER_EMAIL
+
+  latest:
+    image: docker
     repo: plugins/drone-terraform
-    tag: latest
+    tags: [ "latest", "1.0", "1" ]
     when:
       branch: master
-  docker:
-    username: $$DOCKER_USER
-    password: $$DOCKER_PASS
-    email: $$DOCKER_EMAIL
-    repo: plugins/drone-terraform
-    tag: develop
-    when:
-      branch: develop
+      event: push
 
 plugin:
   name: Terraform