[upd] upgrade httpx 0.19.0

adjust searx.network module to the new internal API
see https://github.com/encode/httpx/pull/1522

searx/network/__init__.py

@@ -172,7 +172,7 @@ async def stream_chunk_to_queue(network, queue, method, url, **kwargs):
             async for chunk in response.aiter_raw(65536):
                 if len(chunk) > 0:
                     queue.put(chunk)
-    except httpx.ResponseClosed:
+    except httpx.StreamClosed:
         # the response was queued before the exception.
         # the exception was raised on aiter_raw.
         # we do nothing here: in the finally block, None will be queued