Updating mongo version as per bobby rule. (#64)

Author: ghchapman

project/AppDependencies.scala

@@ -6,7 +6,7 @@ object AppDependencies {
   lazy val libraryDependencies = compile ++ test
 
   private lazy val bootstrapVersion = "6.2.0"
-  private lazy val hmrcMongoVersion = "0.64.0"
+  private lazy val hmrcMongoVersion = "0.68.0"
   private lazy val scalaJVersion = "2.4.2"
 
   private lazy val compile = Seq(
@@ -22,4 +22,4 @@ object AppDependencies {
     "org.mockito" %% "mockito-scala-scalatest" % "1.16.46" % "test, it"
   )
 
-}
+}