Bump sphinx-autobuild from 2020.9.1 to 2021.3.14

Bumps [sphinx-autobuild](https://github.com/executablebooks/sphinx-autobuild) from 2020.9.1 to 2021.3.14.
- [Release notes](https://github.com/executablebooks/sphinx-autobuild/releases)
- [Changelog](https://github.com/executablebooks/sphinx-autobuild/blob/main/NEWS.rst)
- [Commits](https://github.com/executablebooks/sphinx-autobuild/commits)

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

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

Author: dependabot[bot]

poetry.lock

@@ -46,7 +46,7 @@ pytest-django = "^4.1.0"
 pygments = "^2.7.4"
 xdoctest = "^0.15.0"
 sphinx = "^4.0.2"
-sphinx-autobuild = "^2020.9.1"
+sphinx-autobuild = "^2021.3.14"
 darglint = "^1.5.8"
 flake8-docstrings = "^1.5.0"
 flake8-rst-docstrings = "^0.2.3"