[DEPENDABOT] Update Actions: Bump actions/cache from 4 to 5

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 5.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](https://github.com/actions/cache/compare/v4...v5)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/django.yml

@@ -64,7 +64,7 @@ jobs:
         echo "$HOME/.cargo/bin" >> $GITHUB_PATH
 
     - name: Cache UV dependencies
-      uses: actions/cache@v4
+      uses: actions/cache@v5
       with:
         path: ~/.cache/uv
         key: ${{ runner.os }}-uv-${{ hashFiles('backend/pyproject.toml') }}