Bump asgiref from 3.11.1 to 3.12.1

Bumps [asgiref](https://github.com/django/asgiref) from 3.11.1 to 3.12.1.
- [Changelog](https://github.com/django/asgiref/blob/main/CHANGELOG.txt)
- [Commits](django/asgiref@3.11.1...3.12.1)

---
updated-dependencies:
- dependency-name: asgiref
  dependency-version: 3.12.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

backend/requirements.txt

@@ -1,4 +1,4 @@
-asgiref==3.11.1
+asgiref==3.12.1
 astroid==3.3.11
 attrs==26.1.0
 certifi==2026.6.17