restore package.json

Tools/Gulp/package.json

@@ -12,8 +12,5 @@
         "install": "cd ../../ && npm install && cd Playground/ && npm install && cd ../Viewer && npm install && cd ../Tools/Gulp/",
         "build": "gulp --max-old-space-size=8192 --tsLintFix",
         "start": "gulp run --max-old-space-size=8192"
-    },
-    "dependencies": {
-        "gulp": "^4.0.2"
     }
 }