Update sbt-ci-release to 1.6.0 (#348)

Author: scala-steward

project/plugins.sbt

@@ -2,6 +2,6 @@ addSbtPlugin("org.scoverage" % "sbt-scoverage" % "2.1.0")
 
 addSbtPlugin("com.github.sbt" % "sbt-github-actions" % "0.24.0")
 
-addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.5.12")
+addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.6.0")
 
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.2")