Bump urllib3 from 2.5.0 to 2.6.0 in /.requirements

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]

.requirements/docs.txt

@@ -139,7 +139,7 @@ traitlets==5.8.1
     #   matplotlib-inline
 unyt==2.9.3
     # via -r engineering.in
-urllib3==2.5.0
+urllib3==2.6.0
     # via requests
 watchdog==2.2.1
     # via mkdocs