Merge pull request #87 from typelevel/update/sbt-typelevel-0.6.0

Update sbt-typelevel, sbt-typelevel-site to 0.6.0

Author: armanbilge

project/plugins.sbt

@@ -1,3 +1,3 @@
-addSbtPlugin("org.typelevel" % "sbt-typelevel"      % "0.5.4")
-addSbtPlugin("org.typelevel" % "sbt-typelevel-site" % "0.5.4")
+addSbtPlugin("org.typelevel" % "sbt-typelevel"      % "0.6.0")
+addSbtPlugin("org.typelevel" % "sbt-typelevel-site" % "0.6.0")
 addSbtPlugin("org.scala-js"  % "sbt-scalajs"        % "1.13.2")