Update version to 1.3

Author: yflory

src/xwiki/this.js

@@ -2,5 +2,5 @@ Package(function (pack, XWiki) {
     pack.setName("Realtime Editor Frontend");
     pack.setDescription("Collaboratively edit your XWiki Documents with others");
     pack.setExtensionId("org.xwiki.contrib:xwiki-contrib-rtfrontend");
-    pack.setXarName("realtime-frontend-1.2.xar")
+    pack.setXarName("realtime-frontend-1.3.xar")
 });