Bump sphinx-autoapi from 1.7.0 to 1.8.3

Bumps [sphinx-autoapi](https://github.com/readthedocs/sphinx-autoapi) from 1.7.0 to 1.8.3.
- [Release notes](https://github.com/readthedocs/sphinx-autoapi/releases)
- [Changelog](https://github.com/readthedocs/sphinx-autoapi/blob/master/CHANGELOG.rst)
- [Commits](readthedocs/sphinx-autoapi@v1.7.0...v1.8.3)

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

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

Author: dependabot[bot]

docs/requirements.txt

@@ -1,3 +1,3 @@
 Sphinx==3.5.3
-sphinx-autoapi==1.7.0
+sphinx-autoapi==1.8.3
 sphinx-material==0.0.32