Bump downshift from 7.2.1 to 8.4.0

Bumps [downshift](https://github.com/downshift-js/downshift) from 7.2.1 to 8.4.0.
- [Release notes](https://github.com/downshift-js/downshift/releases)
- [Changelog](https://github.com/downshift-js/downshift/blob/master/CHANGELOG.md)
- [Commits](downshift-js/downshift@v7.2.1...v8.4.0)

---
updated-dependencies:
- dependency-name: downshift
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -45,7 +45,7 @@
     "cross-env": "^7.0.3",
     "dayjs": "^1.11.10",
     "diff": "^5.2.0",
-    "downshift": "^7.2.1",
+    "downshift": "^8.4.0",
     "email-validator": "^2.0.4",
     "github-slugger": "^2.0.0",
     "hast-util-find-and-replace": "^5.0.1",