Use new docker image with updated cache after the switch to 2.12

OlivierBlanvillain · OlivierBlanvillain · commit 5991248d338c · 2017-08-30T10:47:14.000+02:00
diff --git a/.drone.yml b/.drone.yml
@@ -8,7 +8,7 @@
 
 pipeline:
   test:
-    image: lampepfl/dotty:07-06-2017
+    image: lampepfl/dotty:2017-08-30
     pull: true
     commands:
       - ./project/scripts/sbt "${CI_TEST}"
