python3.pkgs.webargs: fix tests with newer pytest-asyncio (#438337)

Author: mkg20001

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

@@ -16,6 +16,7 @@
   pyramid,
   falcon,
   aiohttp,
+  fetchpatch,
 }:
 
 buildPythonPackage rec {
@@ -28,6 +29,13 @@ buildPythonPackage rec {
     hash = "sha256-DGF97BntTx/2skfNc4VelJ2HBS1xkAk4tx8Mr9kvGRs=";
   };
 
+  patches = [
+    (fetchpatch {
+      url = "https://github.com/marshmallow-code/webargs/commit/a6a5043ee34b0a22885b3625de6d4fdffc3b715b.patch";
+      hash = "sha256-EFe76SAklgmBjfM6K8PkB0vHMCSlZ9EKAW9AbnxKmPA=";
+    })
+  ];
+
   build-system = [ flit-core ];
 
   dependencies = [ marshmallow ];