Compile:Doc error with Scala 2.12.8 - Upgrade to 2.12.10

There is an error with cross compilation that only surfaces in our doc
(not compile phase) the fix is in scala 2.12.9.

Author: RussellSpitzer

project/Versions.scala

@@ -19,7 +19,7 @@ object Versions {
 
 
   lazy val scala211 = "2.11.7"
-  lazy val scala212 = "2.12.8"
+  lazy val scala212 = "2.12.10"
 
   /* For `scalaBinaryVersion.value outside an sbt task. */
   lazy val scalaBinary = scala212.dropRight(2)