Update sbt-pgp to 2.3.1

Author: scala-steward

project/plugins.sbt

@@ -2,5 +2,5 @@ addSbtPlugin("org.bitlap" % "sbt-kotlin-plugin" % "4.0.0")
 addSbtPlugin("com.github.sbt" % "sbt-release" % "1.4.0")
 addSbtPlugin("net.aichler" % "sbt-jupiter-interface" % "0.11.1")
 addSbtPlugin("org.scalameta" % "sbt-mdoc" % "2.5.2")
-addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.2.1")
+addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")
 addSbtPlugin("org.typelevel" % "sbt-tpolecat" % "0.5.1")