Bump pytest from 8.4.2 to 9.0.0 (#37)

Author: dependabot[bot]

poetry.lock

@@ -12,7 +12,7 @@ pandapower = "^2.14.11"
 simbench = "^1.5.3"
 
 [tool.poetry.group.dev.dependencies]
-pytest = "^8.4.2"
+pytest = "^9.0.0"
 flake8 = "^7.3.0"
 flake8-black = "^0.4.0"
 flake8-isort = "^7.0.0"