Attempting using Ruby image for dpl instead

.gitlab-ci.yml

@@ -17,6 +17,7 @@ test:
 
 deploy:
     stage: deploy
-    image: heroku/heroku:latest
-    script:  
+    image: ruby:latest
+    script:
+      - gem install dpl 
       - dpl --provider=heroku --app=jlp19-simplewebapp --api-key=$Heroku_API_Key