Bump numpydoc from 1.3.1 to 1.4.0 in /requirements

Bumps [numpydoc](https://github.com/numpy/numpydoc) from 1.3.1 to 1.4.0.
- [Release notes](https://github.com/numpy/numpydoc/releases)
- [Changelog](https://github.com/numpy/numpydoc/blob/main/doc/release_notes.rst)
- [Commits](numpy/numpydoc@v1.3.1...v1.4.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements/requirements_docs.txt

@@ -5,7 +5,7 @@ imageio==2.19.3
 jupyter_sphinx==0.3.2
 jupyterlab>=3.2.8
 matplotlib==3.5.2
-numpydoc==1.3.1
+numpydoc==1.4.0
 pandas==1.4.2
 plotly==5.8.2
 ansys-sphinx-theme==0.4.0