Update flake8 config.

Author: domdfcoding

tox.ini

@@ -63,7 +63,7 @@ deps =
     git+https://github.com/PyCQA/pydocstyle@5118faa7173b0e5bbc230c4adf628758e13605bf
     git+https://github.com/domdfcoding/flake8-quotes.git
     git+https://github.com/domdfcoding/flake8-rst-docstrings.git
-    git+https://github.com/domdfcoding/flake8-rst-docstrings-sphinx.git@v2
+    git+https://github.com/domdfcoding/flake8-rst-docstrings-sphinx.git
     pygments>=2.7.1
 commands = python3 -m flake8_rst_docstrings_sphinx flake8_github_actions --allow-toolbox {posargs}