chore(deps): update github artifact actions

Author: renovate[bot]

.github/workflows/server-tests.yml

@@ -42,7 +42,7 @@ jobs:
         run: |
           coverage run manage.py test
       - name: Upload coverage report
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: coverage-data-${{ matrix.python-version }}
           path: ./server/.coverage.*
@@ -63,7 +63,7 @@ jobs:
           python -m pip install --upgrade pip
           pip install coverage
       - name: Download coverage reports from all runners
-        uses: actions/download-artifact@v6.0.0
+        uses: actions/download-artifact@v7.0.0
         with:
           path: ${{ github.workspace }}/
           merge-multiple: true