Update sbt-ci-release to 1.5.9

Author: scala-steward

project/plugins.sbt

@@ -1,4 +1,4 @@
 libraryDependencies += "org.scala-sbt" %% "scripted-plugin" % sbtVersion.value
-addSbtPlugin("com.geirsson" % "sbt-ci-release" % "1.5.7")
+addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.5.9")
 addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.10.0")
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.3")