Bump actions/upload-artifact from 6 to 7

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>

Author: dependabot[bot]

.github/workflows/testing.yml

@@ -154,7 +154,7 @@ jobs:
 
       - name: Upload coverage files as artifact for coverage upload job
         if: ${{ matrix.config.os == 'ubuntu-latest' && matrix.config.resolution == 'highest' }}
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: coverage-files-artifact-${{ matrix.config.python }}
           if-no-files-found: error
@@ -163,7 +163,7 @@ jobs:
 
       - name: Upload DB dump
         if: failure()
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: db_dump_${{ matrix.config.os }}_${{ matrix.config.python }}_${{ matrix.config.resolution }}
           path: test_folder