Bump promisify-child-process from 3.1.4 to 4.1.0 in /desktop (#1155)

Summary:
Quite keen on this as it removes a babel runtime dependency.

Pull Request resolved: https://github.com/facebook/flipper/pull/1155

Reviewed By: nikoant

Differential Revision: D21522869

Pulled By: passy

fbshipit-source-id: 66e272e1b6a6eb78a51038f20a1717ba0196ec2c

desktop/plugins/kaios-allocations/package.json

@@ -20,7 +20,7 @@
   },
   "dependencies": {
     "firefox-client": "0.3.0",
-    "promisify-child-process": "^3.1.1"
+    "promisify-child-process": "^4.1.0"
   },
   "resolutions": {
     "minimist": "1.2.3"