Replacing cocos2d/cocos2d-html5 with cocos/cocos-engine (#3724)

cocos2d/cocos2d-html5 is not maintained anymore, cocos-engine is the next generation game engine of Cocos for cross platform game development including web and native

Author: pandamicro

collections/game-engines/index.md

@@ -23,7 +23,7 @@ items:
  - WhitestormJS/whs.js
  - wellcaffeinated/PhysicsJS
  - playcanvas/engine
- - cocos2d/cocos2d-html5
+ - cocos/cocos-engine
  - craftyjs/Crafty
  - pixijs/pixijs
  - renpy/renpy
@@ -38,7 +38,6 @@ items:
  - amethyst/amethyst
  - orx/orx
  - nCine/nCine
- - cocos/cocos-engine
  - love2d/love
  - coronalabs/corona
  - hajimehoshi/ebiten