update Github auth to Basic Authentication

we got this email from github back in February 2020:

> On February 6th, 2020 at 21:41 (UTC) your application (building-blocks-prod) used its `client_id` and `client_secret` (with the User-Agent Bl.ock Builder) as part of a set of query parameters to access an endpoint through the GitHub API:

> https://api.github.com/gists/bfadecc96183c48d13b7b90bcf358a61

> Please use Basic Authentication instead as using OAuth credentials in query parameters has been deprecated.

> Depending on your API usage, we'll be sending you this email reminder at most once every 3 days.
Just one URL that was accessed with a User-Agent combination will be listed in the email reminder, not all.

> Visit https://developer.github.com/changes/2019-11-05-deprecated-passwords-and-authorizations-api/#authenticating-using-query-parameters for more information.

> Thanks,
> The GitHub Team