Update pytest to 9.0.0 and remove pytest-subtests

Author: jb3

pyproject.toml

@@ -38,9 +38,8 @@ dev = [
     "coverage==7.11.0",
     "httpx==0.28.1",
     "pre-commit==4.3.0",
-    "pytest==8.4.2",
+    "pytest==9.0.0",
     "pytest-cov==7.0.0",
-    "pytest-subtests==0.14.1",
     "pytest-xdist==3.8.0",
     "ruff==0.14.2",
     "taskipy==1.14.1",