Disable PT030 for legacy tests

This complains that `DeprecationWarning` is too broad, and I really
don't care.

Disable via per-file-ignore setting, because ruff conflicts with
itself when trying to disable via magic stanza in the file (apparently
`ruff: noqa` doesn't work if there's a leading space, but then ruff
format is amgy)

Author: masklinn

pyproject.toml

@@ -77,6 +77,9 @@ classes = ["OS"]
 known-first-party = ["ua_parser"]
 combine-as-imports = true
 
+[tool.ruff.lint.per-file-ignores]
+"tests/test_legacy.py" = ["PT030"]
+
 [tool.mypy]
 python_version = "3.9"
 files = "src,tests"