Update pytest version from 8 to 9

Author: fabaff

pyproject.toml

@@ -28,7 +28,7 @@ httpx = ">=0.28,<1"
 
 [tool.poetry.dev-dependencies]
 black = "^25.12"
-pytest = "^8"
+pytest = "^9"
 isort = "^5.11"
 pytest-httpx = ">0.15,<1"
 pytest-asyncio = "^0.16.0"