Update sbt-version-policy to 1.0.0 (#520)

Author: scala-steward

Diff for: project/plugins.sbt

@@ -10,4 +10,4 @@ addSbtPlugin("org.portable-scala" % "sbt-scala-native-crossproject" % "1.0.0")
 addSbtPlugin("org.scala-js" % "sbt-scalajs" % scalaJSVersion)
 addSbtPlugin("org.scala-native" % "sbt-scala-native" % scalaNativeVersion)
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.6.0")
-addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % "1.0.0-RC5")
+addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % "1.0.0")