enforce npm version

package.json

@@ -3,6 +3,9 @@
   "version": "0.4.0-beta1",
   "description": "Explore your message queues",
   "main": "dist/src/electron.js",
+  "engines": {
+    "npm": "16"
+  },
   "scripts": {
     "start": "electron .",
     "test": "yarn test:app && yarn test:backend",
@@ -113,4 +116,4 @@
     "sha1": "^1.1.1",
     "yarn-run-all": "^3.1.1"
   }
-}
+}