ruff: Configure hacking as external linter

Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
Change-Id: Ic8f81e2df7c310f52e5b88dda94762bc0a2b7948

pyproject.toml

@@ -88,7 +88,7 @@ show_column_numbers = true
 show_error_context = true
 strict = true
 # keep this in-sync with 'mypy.exclude' in '.pre-commit-config.yaml'
-exclude = '(?x)(doc | releasenotes)'
+exclude = "(?x)(doc | releasenotes)"
 
 [[tool.mypy.overrides]]
 module = ["keystoneauth1.tests.unit.*"]
@@ -108,6 +108,7 @@ line-length = 79
 
 [tool.ruff.lint]
 select = ["C4", "E4", "E5", "E7", "E9", "F", "G", "LOG", "S", "UP"]
+external = ["H"]
 ignore = [
     "S101",  # asserts are only used for type narrowing
 ]