Deps: Bump whatwg-fetch from 3.6.2 to 3.6.18

Bumps [whatwg-fetch](https://github.com/github/fetch) from 3.6.2 to 3.6.18.
- [Release notes](https://github.com/github/fetch/releases)
- [Changelog](https://github.com/JakeChampion/fetch/blob/master/CHANGELOG.md)
- [Commits](JakeChampion/fetch@v3.6.2...v3.6.18)

---
updated-dependencies:
- dependency-name: whatwg-fetch
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -66,7 +66,7 @@
     "redux-thunk": "^2.4.2",
     "styled-components": "^4.4.1",
     "uuid": "^9.0.0",
-    "whatwg-fetch": "^3.6.2"
+    "whatwg-fetch": "^3.6.18"
   },
   "scripts": {
     "test": "react-scripts test --env=jest-environment-jsdom",