Bump urllib3 in /docs in the pip group across 1 directory

Bumps the pip group with 1 update in the /docs directory: [urllib3](https://github.com/urllib3/urllib3).


Updates `urllib3` from 1.26.19 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@1.26.19...2.6.0)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-version: 2.6.0
  dependency-type: direct:production
  dependency-group: pip
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -26,4 +26,4 @@ sphinxcontrib-htmlhelp==2.0.0
 sphinxcontrib-jsmath==1.0.1
 sphinxcontrib-qthelp==1.0.3
 sphinxcontrib-serializinghtml==1.1.5
-urllib3==1.26.19
+urllib3==2.6.0