Migrate OpenWeaterMap to new library (support API 3.0) (#116870)

Co-authored-by: J. Nick Koston <nick@koston.org>

homeassistant/components/openweathermap/utils.py

@@ -0,0 +1,20 @@
+"""Util functions for OpenWeatherMap."""
+
+from pyopenweathermap import OWMClient, RequestError
+
+
+async def validate_api_key(api_key, mode):
+    """Validate API key."""
+    api_key_valid = None
+    errors, description_placeholders = {}, {}
+    try:
+        owm_client = OWMClient(api_key, mode)
+        api_key_valid = await owm_client.validate_key()
+    except RequestError as error:
+        errors["base"] = "cannot_connect"
+        description_placeholders["error"] = str(error)
+
+    if api_key_valid is False:
+        errors["base"] = "invalid_api_key"
+
+    return errors, description_placeholders