check-against-readme always looks for the project-level README

The token is definitely being passed in, but for whatever reason isn't being found.

``` bash
Ensure coverage has not dropped 📈4s
GITHUB_TOKEN: ***
Run DEBUG=check-code-coverage npx set-gh-status --check-against-readme
DEBUG=check-code-coverage npx set-gh-status --check-against-readme
shell: /bin/bash -e {0}
env:
GITHUB_TOKEN: ***
npx: installed 69 in 3.549s
Token must be provided!
##[error]Process completed with exit code 1.
```

It looks like this package assumes everything is at the root folder. After adding `cd clients/html &&` to the npx line, it works, but then it's looking for the badge at the _root-level_ `README` which doesn't have a badge.