pin node version

Author: colinrcummings

package.json

@@ -47,5 +47,8 @@
     "eslint-plugin-react": "^7.11.1",
     "gh-pages": "^2.0.1",
     "prettier": "^1.14.2"
+  },
+  "engines": {
+    "node": ">=11.4.0"
   }
 }