[plugins.json] Add cocoapods-xzb

[ZhiBinXiao]

Please add the following entry to the plugins.json file:

{
  "gem": "cocoapods-xzb",
  "name": "CocoaPods Xzb",
  "author": "肖志斌",
  "url": "https://github.com/EXAMPLE/cocoapods-xzb",
  "description": "A longer description of cocoapods-xzb."
}