improve timestamps and permissions for jar outputs

* now attributes are applied to all jars  e.g. freemarker-gae-2.3.33-sources.jar freemarker-gae-2.3.33-javadoc.jar freemarker-gae-2.3.33.jar
diff --git a/build.gradle.kts b/build.gradle.kts
index dd1bf0b..d6f5f67 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -39,7 +39,7 @@
 
 tasks.withType<AbstractArchiveTask>().configureEach {
 
-  if (name == "jar") {  
+  if (archiveFileName.get().endsWith(".jar")) {  
     // make contents of freemarker.jar reproducible
     isPreserveFileTimestamps = false
     isReproducibleFileOrder = true