python310Packages.pyspcwebgw: test in asyncio auto mode

pkgs/development/python-modules/pyspcwebgw/default.nix

···
   ];
 
   pytestFlagsArray = [
-    "--asyncio-mode=legacy"
+    "--asyncio-mode=auto"
   ];
 
   pythonImportsCheck = [ "pyspcwebgw" ];