bump scala-version

SethTisue · SethTisue · commit fdb03c97007c · 2019-03-05T07:33:17.000-08:00
I will add this to the Scala release steps, since obviously we
always forget
diff --git a/_config.yml b/_config.yml
@@ -15,7 +15,7 @@ keywords:
 - Document
 - Guide
 
-scala-version: 2.12.2
+scala-version: 2.12.8
 
 collections:
   style:
