fix: graphql/enterprise/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/npm:marked:20170112
- https://snyk.io/vuln/npm:marked:20170815
- https://snyk.io/vuln/npm:marked:20170815-1
- https://snyk.io/vuln/npm:marked:20170907
- https://snyk.io/vuln/npm:marked:20180225
- https://snyk.io/vuln/npm:react-dom:20180802

Author: snyk-bot

graphql/enterprise/package.json

@@ -3,10 +3,10 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
-    "graphiql": "^0.10.2",
+    "graphiql": "^0.11.11",
     "primer-css": "^6.0.0",
     "react": "^15.5.4",
-    "react-dom": "^15.5.4"
+    "react-dom": "^16.0.1"
   },
   "scripts": {
     "build": "node scripts/build.js"