Snyk provider auth not working

It looks like there's been a change in behaviour when the HTTP client was changed to resty? The snyk provider in 0.5.1 appears to throw an authentication error.

```~~~ REQUEST ~~~
GET /rest/self?version=2022-09-15~experimental HTTP/1.1
HOST : api.snyk.io
HEADERS:
Authorization: Bearer
User-Agent: bomber
BODY :
***** NO CONTENT *****```

Note this is now using Bearer auth, rather than token, which is likely why this is failing.

Looking at the upstream project, we need to use `SetAuthScheme` and set to `token` I think.

I'll try and get a PR together unless someone gets there first. cc. @mcombuechen