For some reason Terraform decided that it would otherwise like
to *delete* this configuration, which is undesirable.
Note that there is a "magic" special behaviour when the `alias` and
`provider_id` are set to the name of a built-in supported
provider (github, gitlab etc.), which lets us skip the
authorization_url setup.
Change-Id: Ib66154c2896dda162c57bdc2d7964a9fa4e15f20
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6706
Tested-by: BuildkiteCI
Reviewed-by: lukegb <lukegb@tvl.fyi>