Add @types to monaco dev deps

build/monaco/package.json

@@ -13,6 +13,10 @@
     "url": "https://github.com/Microsoft/vscode/issues"
   },
   "devDependencies": {
+    "@types/minimist": "^1.2.0",
+    "@types/mocha": "^2.2.39",
+    "@types/semver": "^5.3.30",
+    "@types/sinon": "^1.16.34",
     "debounce": "^1.0.0",
     "eslint": "^3.4.0",
     "event-stream": "^3.1.7",