Deprecate the Legacy Works with Nest API (#63027)

homeassistant/components/nest/legacy/__init__.py

@@ -108,6 +108,12 @@ async def async_setup_legacy(hass: HomeAssistant, config: dict) -> bool:
     if DOMAIN not in config:
         return True
 
+    _LOGGER.warning(
+        "The Legacy Works With Nest API is deprecated and support will be removed "
+        "in Home Assistant Core 2022.5; See instructions for using the Smart Device "
+        "Management API at https://www.home-assistant.io/integrations/nest/"
+    )
+
     conf = config[DOMAIN]
 
     local_auth.initialize(hass, conf[CONF_CLIENT_ID], conf[CONF_CLIENT_SECRET])