Upgrade pytest-asyncio to v1.4.0

dev-requirements.txt

@@ -1,7 +1,6 @@
 pytest==9.0.3  # fix CVE-2025-71176; Python 3.10+ required
 flake8==7.3.0
 pytest-timeout==2.4.0
-pytest-asyncio==1.2.0; python_version == '3.9' # version 1.2.0 is the last one supporting Python 3.9
-pytest-asyncio==1.3.0; python_version >= '3.10'
+pytest-asyncio==1.4.0
 httpx==0.28.1
 httpx_ws==0.7.2  # upgrading leads to failures in tests