Update sbt-pgp to 2.2.0 (#115)

Author: paoloboni

project/plugins.sbt

@@ -1,5 +1,5 @@
 addSbtPlugin("org.scalameta"             % "sbt-scalafmt"  % "2.4.6")
-addSbtPlugin("com.github.sbt"            % "sbt-pgp"       % "2.1.2")
+addSbtPlugin("com.github.sbt"            % "sbt-pgp"       % "2.2.0")
 addSbtPlugin("org.xerial.sbt"            % "sbt-sonatype"  % "3.9.13")
 addSbtPlugin("de.heikoseeberger"         % "sbt-header"    % "5.8.0")
 addSbtPlugin("com.github.sbt"            % "sbt-release"   % "1.1.0")