Send the SmartThings token request credentials as a header

aiohttp deprecates BasicAuth and the per-request auth argument in favour
of encode_basic_auth() plus an Authorization header.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PRmnu5HiXQUaHcHnNCvBSU

homeassistant/components/smartthings/application_credentials.py

@@ -4,7 +4,7 @@ from json import JSONDecodeError
 import logging
 from typing import cast, override
 
-from aiohttp import BasicAuth, ClientError
+from aiohttp import ClientError, encode_basic_auth
 
 from homeassistant.components.application_credentials import (
     AuthImplementation,
@@ -46,7 +46,9 @@ class SmartThingsOAuth2Implementation(AuthImplementation):
         resp = await session.post(
             self.token_url,
             data=data,
-            auth=BasicAuth(self.client_id, self.client_secret),
+            headers={
+                "Authorization": encode_basic_auth(self.client_id, self.client_secret)
+            },
         )
         if resp.status >= 400:
             try: