Fix piping into 'gradle run'

pgpainless-cli/build.gradle

@@ -64,6 +64,8 @@ jar {
 }
 
 run {
+    // https://stackoverflow.com/questions/59445306/pipe-into-gradle-run
+    standardInput = System.in
     // https://discuss.gradle.org/t/how-can-i-provide-command-line-args-to-application-started-with-gradle-run/6474/5
     if (project.hasProperty("appArgs")) {
         args Eval.me(appArgs)