Add support for new Forgejo Authorized Integration feature.

[Bricklou]

Tell us more.

Forgejo recently introduced a new security feature called "Authorized Integration" using OpenID to authorize CI to authenticate against APIs. (see https://forgejo.org/docs/latest/user/api/authorized-integrations/)

Having renovate bot supporting this feature would be a real benefit to reduce security issues related to static token stored in secrets.

[jamietanna]

Interesting - to flesh out the use-case would you be wanting Renovate to take an OpenID Connect ID Token (which is a JSON Web Token) from the environment variables and then use that to authenticate to Forgejo/registries?