chore(deps): bump tough-cookie and sponsorkit in /docs

Removes [tough-cookie](https://github.com/salesforce/tough-cookie). It's no longer used after updating ancestor dependency [sponsorkit](https://github.com/antfu/sponsorkit). These dependencies need to be updated together.


Removes `tough-cookie`

Updates `sponsorkit` from 0.9.1 to 0.9.3
- [Release notes](https://github.com/antfu/sponsorkit/releases)
- [Commits](antfu-collective/sponsorkit@v0.9.1...v0.9.3)

---
updated-dependencies:
- dependency-name: tough-cookie
  dependency-type: indirect
- dependency-name: sponsorkit
  dependency-type: direct:development
...

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