Bump sphinx-notfound-page from 0.8 to 0.8.3

Bumps [sphinx-notfound-page](https://github.com/readthedocs/sphinx-notfound-page) from 0.8 to 0.8.3.
- [Release notes](https://github.com/readthedocs/sphinx-notfound-page/releases)
- [Changelog](https://github.com/readthedocs/sphinx-notfound-page/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/readthedocs/sphinx-notfound-page/compare/0.8...0.8.3)

---
updated-dependencies:
- dependency-name: sphinx-notfound-page
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

requirements-dev.txt

@@ -14,7 +14,7 @@ sphinx-jinja==2.0.2
 sphinx-tabs==3.4.1
 sphinxcontrib-programoutput==0.17
 sphinx-autobuild==2021.3.14
-sphinx-notfound-page==0.8
+sphinx-notfound-page==0.8.3
 myst-parser==0.18.0
 linuxdoc==20211220
 aiounittest==1.4.2