Support Bearer token authentication

[steveszc]

https://developers.cloudflare.com/workers/tooling/api/requests/

According to the Cloudflare docs its possible to include an Authorization header using a Bearer token instead of the full api key.

Auth Headers

All requests to the Cloudflare Workers REST API must

be sent over HTTPS
Send a JSON body (unless otherwise indicated)
contain valid identification headers (Find your Cloudflare Auth info).
    Using API Tokens:
        Authorization - provide an API token in standard Bearer <token> format.
    Using Email and Global API Key
        X-Auth-Email - the email address attached to your Cloudflare profile.
        X-Auth-Key - the Global API key attached to your Cloudflare profile.

Would be great to support this scheme in addition to the email/api key scheme.