Bump sphinx-reredirects from 0.1.3 to 0.1.6 in /requirements (#2182)

Bumps [sphinx-reredirects](https://github.com/documatt/sphinx-reredirects) from 0.1.3 to 0.1.6.
- [Commits](documatt/sphinx-reredirects@v0.1.3...v0.1.6)

---
updated-dependencies:
- dependency-name: sphinx-reredirects
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements/requirements_docs.txt

@@ -11,7 +11,7 @@ sphinx-copybutton==0.5.2
 sphinx-gallery==0.19.0
 sphinx-jinja==2.0.2
 sphinx-notfound-page==1.1.0
-sphinx-reredirects==0.1.3
+sphinx-reredirects==0.1.6
 sphinx_design==0.6.1
 sphinxcontrib-napoleon==0.7
 vtk==9.3.1