MAINT: Bump sphinx from 3.5.3 to 3.5.4
MAINT: Bump sphinx from 3.5.3 to 3.5.4

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 3.5.3 to 3.5.4.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/4.x/CHANGES)
- [Commits](https://github.com/sphinx-doc/sphinx/commits/v3.5.4)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
numpy/numpy,mattip/numpy,pbrod/numpy,anntzer/numpy,rgommers/numpy,endolith/numpy,seberg/numpy,anntzer/numpy,endolith/numpy,charris/numpy,endolith/numpy,rgommers/numpy,mhvk/numpy,simongibbons/numpy,numpy/numpy,anntzer/numpy,seberg/numpy,pdebuyl/numpy,pbrod/numpy,endolith/numpy,mattip/numpy,jakirkham/numpy,mhvk/numpy,pdebuyl/numpy,mhvk/numpy,numpy/numpy,anntzer/numpy,pdebuyl/numpy,simongibbons/numpy,seberg/numpy,pbrod/numpy,jakirkham/numpy,pbrod/numpy,jakirkham/numpy,mattip/numpy,rgommers/numpy,mhvk/numpy,simongibbons/numpy,jakirkham/numpy,simongibbons/numpy,charris/numpy,pbrod/numpy,mattip/numpy,charris/numpy,jakirkham/numpy,mhvk/numpy,charris/numpy,numpy/numpy,pdebuyl/numpy,simongibbons/numpy,rgommers/numpy,seberg/numpy