fix: allow label requests with slashes

[raffis]

Fixes #43

/hack/gen.sh needs master so I guess I don't need to submit the generated code.

[migueleliasweb]

Hi @raffis , I've found some other occurrences that might be impacted by the same issue.

• "/orgs/{org}/actions/runners/{runner_id}/labels/{name}"
• "/repos/{owner}/{repo}/issues/{issue_number}/labels/{name}"
• "/repos/{owner}/{repo}/labels/{name}"

All of these have the same /labels/{name} in the end of them. Could you double check if we need to override these as well?