fix "zh-TW" and "zh-CN" translation not showing (#2758)

gulpfile.js

@@ -27,8 +27,8 @@ const jsonSchemaFilesPatterns = [
 ];
 
 const languages = [
-    { id: "zh-TW", folderName: "cht", transifexId: "zh-hant" },
-    { id: "zh-CN", folderName: "chs", transifexId: "zh-hans" },
+    { id: "zh-tw", folderName: "cht", transifexId: "zh-hant" },
+    { id: "zh-cn", folderName: "chs", transifexId: "zh-hans" },
     { id: "fr", folderName: "fra" },
     { id: "de", folderName: "deu" },
     { id: "it", folderName: "ita" },