Update sbt-pgp to 2.3.1 (#166)

Author: scala-steward

project/plugins.sbt

@@ -8,7 +8,7 @@ addSbtPlugin("pl.project13.scala" % "sbt-jmh"                       % "0.4.7")
 addSbtPlugin("com.eed3si9n"       % "sbt-assembly"                  % "2.3.0")
 addSbtPlugin("com.github.sbt"   % "sbt-native-packager"           % "1.10.4")
 addSbtPlugin("com.eed3si9n"       % "sbt-buildinfo"                 % "0.13.1")
-addSbtPlugin("com.github.sbt"       % "sbt-pgp"                       % "2.3.0")
+addSbtPlugin("com.github.sbt"       % "sbt-pgp"                       % "2.3.1")
 addSbtPlugin("org.xerial.sbt"     % "sbt-sonatype"                  % "3.12.2")
 addSbtPlugin("com.github.sbt"       % "sbt-dynver"                    % "5.1.0")
 addSbtPlugin("de.heikoseeberger"  % "sbt-header"                    % "5.10.0")