* [deps] Update Keycloak dependencies to 18.0.0

> ⚠️ **Compatibility issues**:
>
> Due to a refactoring of Keycloak's `ResourceStore` API this extension will no longer be backwards compatible with Keycloak versions < 18.x.
>
> For details please see https://github.com/keycloak/keycloak/commit/99c06d11023689875b48ef56442c90bdb744c869 and https://github.com/keycloak/keycloak/issues/10447
>