Bump cookie and maildev in /tests/UI

Bumps [cookie](https://github.com/jshttp/cookie) and [maildev](https://github.com/maildev/maildev). These dependencies needed to be updated together.

Updates `cookie` from 0.6.0 to 0.7.1
- [Release notes](https://github.com/jshttp/cookie/releases)
- [Commits](jshttp/cookie@v0.6.0...v0.7.1)

Updates `maildev` from 2.1.0 to 2.2.1
- [Release notes](https://github.com/maildev/maildev/releases)
- [Commits](maildev/maildev@v2.1.0...v2.2.1)

---
updated-dependencies:
- dependency-name: cookie
  dependency-type: indirect
- dependency-name: maildev
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>