Implement delimiter for plugin authors in the version command (#2139)

This change separates authors so that instead of "Authors: xxFLORIIxxAROX" it looks like "Authors: xxFLORII, xxAROX".

src/main/java/cn/nukkit/command/defaults/VersionCommand.java

@@ -77,7 +77,7 @@ public boolean execute(CommandSender sender, String commandLabel, String[] args)
                 if (authors.size() == 1) {
                     sender.sendMessage("Author: " + authorsString[0]);
                 } else if (authors.size() >= 2) {
-                    sender.sendMessage("Authors: " + authorsString[0]);
+                    sender.sendMessage("Authors: " + String.join(", ", authors));
                 }
             } else {
                 sender.sendMessage(new TranslationContainer("nukkit.command.version.noSuchPlugin"));