Bump sphinx-argparse from 0.3.2 to 0.4.0

Bumps [sphinx-argparse](https://github.com/ashb/sphinx-argparse) from 0.3.2 to 0.4.0.
- [Release notes](https://github.com/ashb/sphinx-argparse/releases)
- [Changelog](https://github.com/ashb/sphinx-argparse/blob/main/docs/changelog.rst)
- [Commits](sphinx-doc/sphinx-argparse@0.3.2...v0.4.0)

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

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

Author: dependabot[bot]

doc/requirements.txt

@@ -1,5 +1,5 @@
 sphinx-rtd-theme==1.1.1
-sphinx-argparse==0.3.2
+sphinx-argparse==0.4.0
 sphinxcontrib-applehelp==1.0.2; python_version >= "3.5"
 sphinxcontrib-devhelp==1.0.2; python_version >= "3.5"
 sphinxcontrib-htmlhelp==2.0.0; python_version >= "3.5"