Bump certifi from 2020.4.5.2 to 2022.12.7 in /doc/.sphinx

Bumps [certifi](https://github.com/certifi/python-certifi) from 2020.4.5.2 to 2022.12.7.
- [Release notes](https://github.com/certifi/python-certifi/releases)
- [Commits](certifi/python-certifi@2020.04.05.2...2022.12.07)

---
updated-dependencies:
- dependency-name: certifi
  dependency-type: direct:production
...

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

doc/.sphinx/requirements.txt

@@ -7,7 +7,7 @@ recommonmark==0.6
 ## The following requirements were added by pip freeze:
 alabaster==0.7.12
 Babel==2.8.0
-certifi==2020.4.5.2
+certifi==2022.12.7
 chardet==3.0.4
 click==7.1.2
 sphinxcontrib-mermaid==0.4.0