fix: upgrade multiple dependencies with Snyk (#43)

Snyk has created this PR to upgrade:
  - react from 16.5.2 to 16.13.1.
    See this package in NPM: https://www.npmjs.com/package/react
  - react-dom from 16.5.2 to 16.13.1.
    See this package in NPM: https://www.npmjs.com/package/react-dom

See this project in Snyk:
https://app.snyk.io/org/yowainwright/project/db3755b8-83ff-486a-9398-cc2d2d39d420?utm_source=github&utm_medium=upgrade-pr

finished-application/frontend/package.json

@@ -30,10 +30,10 @@
     "next-with-apollo": "^3.2.0",
     "nprogress": "^0.2.0",
     "prop-types": "^15.6.2",
-    "react": "^16.5.2",
+    "react": "^16.13.1",
     "react-adopt": "^0.6.0",
     "react-apollo": "^2.2.1",
-    "react-dom": "^16.5.2",
+    "react-dom": "^16.13.1",
     "react-stripe-checkout": "^2.6.3",
     "react-transition-group": "^2.9.0",
     "styled-components": "^3.4.9",