upgrade to sbt-native-packager 1.0.6

we recently upgraded to 1.0.4, but that caused a regression so the
change never received full testing yet.  the regression has bene
fixed, so as long as we're going to do a new round of testing, let's
test the latest latest

Author: SethTisue

project/plugins.sbt

@@ -1,6 +1,6 @@
 scalacOptions ++= Seq("-deprecation", "-feature", "-Xlint")
 
-addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.0.4")
+addSbtPlugin("com.typesafe.sbt" % "sbt-native-packager" % "1.0.6")
 
 addSbtPlugin("com.typesafe.sbt" % "sbt-s3" % "0.8")