pydocstyle is not needed to run tests.
See also https://github.com/Bachmann1234/diff_cover/issues/424

--- diff_cover-9.2.0/pyproject.toml.orig
+++ diff_cover-9.2.0/pyproject.toml
@@ -56,7 +56,6 @@
 flake8 = "^5.0.4"
 pyflakes = "^2.5.0"
 pylint = "^3.2.7"
-pydocstyle = "^6.1.1"
 black = "^24.8.0"
 isort = "^5.13.2"