chore(deps): bump actions/download-artifact from 6 to 7 (#126)

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

---
updated-dependencies:
- dependency-name: actions/download-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/ci.yml

@@ -91,7 +91,7 @@ jobs:
         run: uv tool install poethepoet
 
       - name: Load built wheel file
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: power-grid-model-ds
           path: dist/
@@ -117,7 +117,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Load built wheel file
-        uses: actions/download-artifact@v6
+        uses: actions/download-artifact@v7
         with:
           name: power-grid-model-ds
           path: dist/