Pin dependencies

Author: renovate-bot

package.json

@@ -9,8 +9,8 @@
     "graphql-tag-pluck": "0.8.4",
     "merge-graphql-schemas": "1.7.0",
     "netlify-lambda": "1.6.3",
-    "react": "^16.9.0",
-    "react-dom": "^16.9.0",
+    "react": "16.9.0",
+    "react-dom": "16.9.0",
     "react-scripts": "3.1.1"
   },
   "scripts": {