Replace has_mean with mean_type in mill external statistics (home-assistant#153985)

Author: emontnemery

homeassistant/components/mill/coordinator.py

@@ -10,7 +10,11 @@
 from mill_local import Mill as MillLocal
 
 from homeassistant.components.recorder import get_instance
-from homeassistant.components.recorder.models import StatisticData, StatisticMetaData
+from homeassistant.components.recorder.models import (
+    StatisticData,
+    StatisticMeanType,
+    StatisticMetaData,
+)
 from homeassistant.components.recorder.statistics import (
     async_add_external_statistics,
     get_last_statistics,
@@ -147,7 +151,7 @@ async def _async_update_data(self):
                     )
                 )
             metadata = StatisticMetaData(
-                has_mean=False,
+                mean_type=StatisticMeanType.NONE,
                 has_sum=True,
                 name=f"{heater.name}",
                 source=DOMAIN,