Bump sphinx from 4.0.3 to 4.1.0

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 4.0.3 to 4.1.0.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/4.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v4.0.3...v4.1.0)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

poetry.lock

@@ -45,7 +45,7 @@ coverage = {extras = ["toml"], version = "^5.3"}
 pytest-django = "^4.1.0"
 pygments = "^2.7.4"
 xdoctest = "^0.15.5"
-sphinx = "^4.0.3"
+sphinx = "^4.1.0"
 sphinx-autobuild = "^2021.3.14"
 darglint = "^1.5.8"
 flake8-docstrings = "^1.5.0"