Update sbt-pgp to 2.3.1

Author: scala-steward-bot

project/plugin.sbt

@@ -1,5 +1,5 @@
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.2")
-addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.0")
+addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")
 addSbtPlugin("com.github.sbt" % "sbt-release" % "1.4.0")
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.12.0")
 addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.17.0")