Bump urllib3 from 2.5.0 to 2.6.3 in /docs

Bumps [urllib3](https://github.com/urllib3/urllib3) from 2.5.0 to 2.6.3.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@2.5.0...2.6.3)

---
updated-dependencies:
- dependency-name: urllib3
  dependency-version: 2.6.3
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -43,4 +43,4 @@ sphinxcontrib-qthelp==2.0.0
 sphinxcontrib-serializinghtml==2.0.0
 tomli==2.2.1 ; python_full_version < '3.11'
 typing-extensions==4.15.0
-urllib3==2.5.0
+urllib3==2.6.3