Update sbt-pgp to 2.3.1

Author: scalikejdbc-bot[bot]

project/plugins.sbt

@@ -1,6 +1,6 @@
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.5.2")
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.9.21")
-addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.0")
+addSbtPlugin("com.github.sbt" % "sbt-pgp" % "2.3.1")
 addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.6.4")
 addSbtPlugin("net.virtual-void" % "sbt-dependency-graph" % "0.9.2")
 addSbtPlugin("org.scoverage" % "sbt-scoverage" % "2.2.2")