Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [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/v3...v4)

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

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

.github/workflows/ci.yml

@@ -32,7 +32,7 @@ jobs:
         pip install -r requirements.txt
 
     - name: Cache StaticFiles
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       id: django_cache
       with:
         path: |
@@ -67,7 +67,7 @@ jobs:
         python3 manage.py collectstatic --noinput
         python3 manage.py collectstatic_js_reverse
 
-    - uses: actions/cache/save@v3
+    - uses: actions/cache/save@v4
       if: steps.django_cache.outputs.cache-hit != 'true'
       with:
         path: |