Update sbt-ci-release to 1.8.0 (#680)

Author: scala-steward

project/plugins.sbt

@@ -4,4 +4,4 @@ addSbtPlugin("ch.epfl.scala" % "sbt-missinglink" % "0.3.6")
 addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.4")
 addSbtPlugin("io.github.davidgregory084" % "sbt-tpolecat" % "0.4.4")
 addSbtPlugin("com.timushev.sbt" % "sbt-rewarn" % "0.1.3")
-addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.7.0")
+addSbtPlugin("com.github.sbt" % "sbt-ci-release" % "1.8.0")