Bump the python-packages group with 3 updates

Bumps the python-packages group with 3 updates: [sphinx](https://github.com/sphinx-doc/sphinx), [furo](https://github.com/pradyunsg/furo) and [blacken-docs](https://github.com/asottile/blacken-docs).


Updates `sphinx` from 7.1.2 to 7.2.2
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES)
- [Commits](sphinx-doc/sphinx@v7.1.2...v7.2.2)

Updates `furo` from 2023.7.26 to 2023.8.19
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2023.07.26...2023.08.19)

Updates `blacken-docs` from 1.15.0 to 1.16.0
- [Changelog](https://github.com/adamchainz/blacken-docs/blob/main/CHANGELOG.rst)
- [Commits](adamchainz/blacken-docs@1.15.0...1.16.0)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: python-packages
- dependency-name: furo
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: python-packages
- dependency-name: blacken-docs
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: python-packages
...

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

setup.py

@@ -69,8 +69,8 @@ def get_version():
     setup_requires=["pytest-runner"],
     extras_require={
         "docs": [
-            "Sphinx==7.1.2",
-            "furo==2023.7.26",
+            "Sphinx==7.2.2",
+            "furo==2023.8.19",
             "sphinx-autobuild",
             "codespell>=2.2.5",
             "blacken-docs",
@@ -84,7 +84,7 @@ def get_version():
             "pytest-asyncio>=0.17",
             "beautifulsoup4>=4.8.1",
             "black==23.7.0",
-            "blacken-docs==1.15.0",
+            "blacken-docs==1.16.0",
             "pytest-timeout>=1.4.2",
             "trustme>=0.7",
             "cogapp>=3.3.0",