Merge pull request #107 from scala-steward/update/sbt-mdoc-2.2.1

Update sbt-mdoc to 2.2.1

Author: vaslabs

project/plugins.sbt

@@ -4,4 +4,4 @@ addSbtPlugin("com.github.gseitz" % "sbt-release"  % "1.0.13")
 addSbtPlugin("com.jsuereth"      % "sbt-pgp"      % "2.0.1")
 addSbtPlugin("org.xerial.sbt"    % "sbt-sonatype" % "3.9.2")
 addSbtPlugin("com.47deg"  % "sbt-microsites" % "1.2.1")
-addSbtPlugin("org.scalameta" % "sbt-mdoc" % "2.2.0" )
+addSbtPlugin("org.scalameta" % "sbt-mdoc" % "2.2.1" )