Release 4.1.2

Fixed #54: Broken on wagtail>=6.2.

• Issue: In wagtail==6.2, the implementation of RoutablePageMixin.route was changed to add the routable_resolver_match attribute to the given request object. get_model_for_url_by_wagtail previously called that method with request=None (because there is no relevant request object available at the time webmentions are processed), so trying to set that attribute on the request fails.
• Fix: get_model_for_url_by_wagtail now creates and passes a dummy instance of HttpRequest when calling that method.