v4.0.0-beta.4 of serverpod_auth_idp_flutter_facebook

Facebook-specific Flutter package for the Serverpod authentication module. Changelog excerpt: - feat: Allows overriding the default cache header for `StaticRoute`and `SpaRoute`from env vars. - feat: Adds opt-in `httpOnly`cookie authentication for web clients. - feat: Generates the column specified as `field=`on relations that require the explicit foreign key. - feat: Introduces the `deferred`and…