Pin pycares<5 to fix pytest CI failure

pycares 5.0.1 removed ares_query_a_result which aiodns 3.5.0 still
references, causing an AttributeError at import time and failing all
tests.

Author: nathanmarlor

requirements.txt

@@ -5,6 +5,7 @@ pytest-homeassistant-custom-component==0.13.269  # Matching version
 psutil-home-assistant  # Not sure why this is needed?
 fnv_hash_fast  # Or this?
 pytest-asyncio
+pycares<5  # pycares 5.0.1 removed ares_query_a_result, incompatible with aiodns 3.5.0
 
 # For pytest. Keep in sync with manifest.json and https://github.com/home-assistant/core/blob/master/requirements_all.txt.
 pyserial==3.5