bump: sbt-ci-release 1.6.0 (was 1.5.12) (#594)

Author: scala-steward

project/plugins.sbt

@@ -6,7 +6,7 @@ addSbtPlugin("com.lightbend.sbt" % "sbt-java-formatter" % "0.8.0")
 addDependencyTreePlugin
 
 // for releasing
-addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.5.12")
+addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.6.0")
 
 //// docs
 addSbtPlugin("com.lightbend.paradox" % "sbt-paradox-dependencies" % "0.2.4")