Bump urllib3 from 2.5.0 to 2.6.0 in /src/backend

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: direct:production
...

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

Author: dependabot[bot]

src/backend/requirements.txt

@@ -342,7 +342,7 @@ typing-inspection==0.4.1
     # via
     #   pydantic
     #   pydantic-settings
-urllib3==2.5.0
+urllib3==2.6.0
     # via
     #   requests
     #   types-requests