Merge pull request scalacenter#2284 from scalacenter/update/sbt-ghpages-0.9.0

Update sbt-ghpages to 0.9.0

Author: bjaglin

project/plugins.sbt

@@ -1,6 +1,6 @@
 addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.11.2")
 addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.13.1")
-addSbtPlugin("com.github.sbt" % "sbt-ghpages" % "0.8.0")
+addSbtPlugin("com.github.sbt" % "sbt-ghpages" % "0.9.0")
 addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % "3.2.1")
 addSbtPlugin("org.scalameta" % "sbt-mdoc" % "2.7.2")
 addSbtPlugin("org.scoverage" % "sbt-scoverage" % "2.3.1")