Add deprecation warning to switchbot yaml config (#62583)

Co-authored-by: Franck Nijhof <git@frenck.dev>

homeassistant/components/switchbot/switch.py

@@ -49,6 +49,12 @@ async def async_setup_platform(
     discovery_info: DiscoveryInfoType | None = None,
 ) -> None:
     """Import yaml config and initiates config flow for Switchbot devices."""
+    _LOGGER.warning(
+        "Configuration of the Switchbot switch platform in YAML is deprecated and "
+        "will be removed in Home Assistant 2022.4; Your existing configuration "
+        "has been imported into the UI automatically and can be safely removed "
+        "from your configuration.yaml file"
+    )
 
     # Check if entry config exists and skips import if it does.
     if hass.config_entries.async_entries(DOMAIN):