Merge pull request #606 from scala-steward/update/mdoc-2.8.1

Update mdoc, sbt-mdoc to 2.8.1

Author: mergify[bot]

project/plugins.sbt

@@ -2,7 +2,7 @@ addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.3.2")
 
 addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.20.1")
 
-addSbtPlugin("org.scalameta" % "sbt-mdoc" % "2.8.0")
+addSbtPlugin("org.scalameta" % "sbt-mdoc" % "2.8.1")
 
 addSbtPlugin("org.scoverage" % "sbt-scoverage" % "2.4.2")