FIX: support HTTPX 0.28

FIX: freeze response markers 🚑️

FIX: incorrect type alias for SOAP `Header` 🐛

FIX: support `HttpUrl` in `ByBindingName` 🐛

FIX: support `HttpUrl` in `ByBindingName` 🐛

NEW: initial SOAP headers support ✨

OPT: Update all non-major dependencies ⬆️

NEW: support callback protocols in the binder ✨

NEW: `QueryArrayParam` marker for HTTP GET parameters ✨

FIX: do not wrap `CancelledError` into `BackendError` 🐛