pyproject: Disable two pytest ruff rules

Different ruff versions have contradicting opinions about how to write
the pytest decorators. Writing them with () as we do now is more
general, so let's keep it that way.

pyproject.toml

@@ -62,3 +62,7 @@ select = [
     "W",       # warnings (mostly whitespace)
     "YTT",     # flake8-2020
 ]
+
+ignore = [
+    "PT001", "PT023", # different versions can't make up their mind how to write decorators
+]