Bump urllib3 from 2.6.0 to 2.6.3 in /requirements/docs

Bumps [urllib3](https://github.com/urllib3/urllib3) from 2.6.0 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@2.6.0...2.6.3)

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

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

Author: dependabot[bot]

requirements/docs/requirements.txt

@@ -23,5 +23,5 @@ sphinxcontrib-jsmath==1.0.1 ; python_version >= "3.9"
 sphinxcontrib-qthelp==2.0.0 ; python_version >= "3.9"
 sphinxcontrib-serializinghtml==2.0.0 ; python_version >= "3.9"
 tomli==2.2.1 ; python_version >= "3.9" and python_version < "3.11"
-urllib3==2.6.0 ; python_version >= "3.9"
+urllib3==2.6.3 ; python_version >= "3.9"
 zipp==3.23.0 ; python_version == "3.9"