How to tell Hedgedoc that it is run behind reverse proxy with SSL offloading?

My version of HedgeDoc is: 1.10.0

What I expected to happen:

I am running Hedgedoc behind a traefik reverse proxy with SSL offloading. Hedgedoc is reachable via https://hedgedoc.mydomain.tld.
I want to integrate it to Authelia with OIDC login. I have configured everything like the documentation says, and have set up the valid redirect_uris in authelia as https://hedgedoc.mydomain.tld/auth/oauth2/callback

What actually happened:

Hedgedoc returns a response to authelia that the redirect_uri is http://hedgedoc.mydomain.tld/auth/oauth2/callback which is denied by Authelia, since the accepted redirect_uri should be reached via HTTPS. So apparently because traefik does all the SSL offloading stuff, Hedgedoc does in fact not know that it is reachable via HTTPS, and i want to change that.

I already tried:

I tried to set CMD_PROTOCOL_USE_SSL: "true" in my docker-compose, but without good results. So, for clarification: How do i set the Hedgedoc base domain with protocol handler?