Bump urllib3 in /docs_src/build in the pip group across 1 directory (#9585)

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


Updates `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
  dependency-group: pip
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs_src/build/requirements.txt

@@ -10,6 +10,6 @@ sortedcontainers==2.4.0
 trio==0.31.0
 trio-websocket==0.12.2
 typing_extensions==4.15.0
-urllib3==2.6.0
+urllib3==2.6.3
 websocket-client==1.9.0
 wsproto==1.2.0