python3Packages.pytest-asyncio: add backports.asyncio.runner to dependencies for python 3.10

pkgs/development/python-modules/pytest-asyncio/default.nix

@@ -3,8 +3,10 @@
   buildPythonPackage,
   callPackage,
   fetchFromGitHub,
+  pythonOlder,
   pytest,
   setuptools-scm,
+  backports-asyncio-runner,
 }:
 
 buildPythonPackage rec {
@@ -27,6 +29,9 @@ buildPythonPackage rec {
   build-system = [ setuptools-scm ];
 
   buildInputs = [ pytest ];
+  dependencies = lib.optionals (pythonOlder "3.11") [
+    backports-asyncio-runner
+  ];
 
   postInstall = ''
     mkdir $testout