switch from coroutine to async/await

With the upgrade to python 3.11, `@asyncio.coroutine` no longer exists. This was preventing the plugin from loading. Switched all instances of `@asyncio.coroutine` to `async def` methods and switched `yield from` to `await`.

custom_components/attributes/sensor.py

@@ -41,8 +41,12 @@
 })
 
 
-@asyncio.coroutine
-def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
+async def async_setup_platform(
+    hass,
+    config,
+    async_add_devices,
+    discovery_info=None
+):
     """Set up the attributes sensors."""
     _LOGGER.info("Starting attribute sensor")
     sensors = []
@@ -200,10 +204,9 @@ def __init__(self, hass, device_id, friendly_name, device_friendly_name,
         self._icon = None
         self._entity = entity_id
 
-    @asyncio.coroutine
-    def async_added_to_hass(self):
+    async def async_added_to_hass(self):
         """Register callbacks."""
-        state = yield from self.async_get_last_state()
+        state = await self.async_get_last_state()
         if state:
             self._state = state.state
 
@@ -258,8 +261,7 @@ def should_poll(self):
         """No polling needed."""
         return False
 
-    @asyncio.coroutine
-    def async_update(self):
+    async def async_update(self):
         """Update the state from the template and the friendly name."""
 
         entity_state = self.hass.states.get(self._entity)