Bump axios and govuk-prototype-kit in /guide

Removes [axios](https://github.com/axios/axios). It's no longer used after updating ancestor dependency govuk-prototype-kit. These dependencies need to be updated together.


Removes `axios`

Updates `govuk-prototype-kit` from 13.16.0 to 13.16.1

---
updated-dependencies:
- dependency-name: axios
  dependency-type: indirect
- dependency-name: govuk-prototype-kit
  dependency-type: indirect
...

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