Bump certifi from 2018.1.18 to 2022.12.7 in /docs

Bumps [certifi](https://github.com/certifi/python-certifi) from 2018.1.18 to 2022.12.7.
- [Release notes](https://github.com/certifi/python-certifi/releases)
- [Commits](certifi/python-certifi@2018.01.18...2022.12.07)

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

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

Author: dependabot[bot]

docs/requirements.txt

@@ -1,7 +1,7 @@
 alabaster==0.7.10
 Babel==2.5.3
 behave==1.2.6
-certifi==2018.1.18
+certifi==2022.12.7
 chardet==3.0.4
 colorama==0.3.9
 coverage==4.5