[plugins.json] Add cocoapods-remove-duplicates

[东方未明]

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

{
  "gem": "cocoapods-remove-duplicates",
  "name": "CocoaPods Remove Duplicates",
  "author": "GaoYu",
  "url": "https://github.com/gaoyuexit/cocoapods-remove-duplicates",
  "description": "remove the duplicate .a .framework in pod install."
}