fix UP015

src/evohomeasync2/client.py

@@ -358,7 +358,7 @@ async def set_schedules(
     evo: EvohomeClient = ctx.obj[SZ_EVO]
 
     # will TypeError if filename is sys.stdin
-    async with aiofiles.open(filename, "r") as fp:  # type: ignore[call-overload]
+    async with aiofiles.open(filename) as fp:  # type: ignore[call-overload]
         content = await fp.read()
 
     success = await _get_tcs(evo, loc_idx).set_schedules(json.loads(content))