gh-action: bump actions/upload-artifact from 6 to 7 (#1665)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v6...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/release.yml

@@ -61,7 +61,7 @@ jobs:
           tar -czf frontend-dist.tar.gz -C frontend/build .
 
       - name: Upload frontend artifact
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: frontend-dist
           path: frontend-dist.tar.gz
@@ -116,7 +116,7 @@ jobs:
           AUR_KEY: ${{ secrets.AUR_KEY }}
 
       - name: Upload backend artifact
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: backend-dist
           path: backend/dist