Update dependency com.github.sbt:sbt-pgp to v2.3.1

Author: renovate[bot]

project/plugins.sbt

@@ -1,6 +1,6 @@
 addSbtPlugin("org.jetbrains" % "sbt-ide-settings" % "1.1.0")
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.9.13")
-addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.2.0-M2")
+addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")
 addSbtPlugin("com.github.sbt" % "sbt-release" % "1.1.0")
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.6")
 addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.10.1")