Update dependency Sphinx to v4.1.1

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
Sphinx (source)	==4.1.0 -> ==4.1.1

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Release Notes

sphinx-doc/sphinx

### [`v4.1.1`](https://togithub.com/sphinx-doc/sphinx/blob/master/CHANGES#Release-411-released-Jul-15-2021) [Compare Source](https://togithub.com/sphinx-doc/sphinx/compare/v4.1.0...v4.1.1) \===================================== ## Dependencies - [#​9434](https://togithub.com/sphinx-doc/sphinx/issues/9434): sphinxcontrib-htmlhelp-2.0.0 or above - [#​9434](https://togithub.com/sphinx-doc/sphinx/issues/9434): sphinxcontrib-serializinghtml-1.1.5 or above ## Bugs fixed - [#​9438](https://togithub.com/sphinx-doc/sphinx/issues/9438): html: HTML logo or Favicon specified as file not being found on output

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[coveralls]

Coverage remained the same at 88.829% when pulling fb2c57bfce6f9ca621fbf95e5ca5d4b3e4b9e0d9 on renovate/sphinx-4.x into 400d83c1edc0b08f20d42ad89ea3473c5fc02c05 on develop.