build: Bump urllib3 from 2.5.0 to 2.6.0 in /docs

Bumps [urllib3](https://github.com/urllib3/urllib3) from 2.5.0 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@2.5.0...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]

docs/requirements.txt

@@ -93,7 +93,7 @@ tomli==2.0.0
     # via pep517
 tornado==6.5.1
     # via livereload
-urllib3==2.5.0
+urllib3==2.6.0
     # via requests
 wheel==0.38.1
     # via pip-tools