Bump urllib3 from 2.2.2 to 2.6.0 in /requirements

Bumps [urllib3](https://github.com/urllib3/urllib3) from 2.2.2 to 2.6.0.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@2.2.2...2.6.0)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-version: 2.6.0
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements/checkdocs.txt

@@ -97,7 +97,7 @@ starlette==0.49.1
     # via sphinx-autobuild
 typing-extensions==4.15.0
     # via starlette
-urllib3==2.2.2
+urllib3==2.6.0
     # via requests
 uvicorn==0.29.0
     # via sphinx-autobuild