Declare env step

.drone.yml

@@ -3,11 +3,13 @@ type: docker
 name: default
 
 steps:
-- name: Build
-  image: golang
+- name: env
+  image: docker
   environment:
     NASA_TOKEN:
       from_secret: nasa_api
+- name: Build
+  image: golang
   commands:
   - go get github.com/reujab/wallpaper
   - go vet -v