Bump actions/upload-artifact from 4 to 6 (#775)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/continuous_integration.yml

@@ -79,7 +79,7 @@ jobs:
         run: composer cs-check
 
       - name: "Archive code coverage results"
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: codeCoverage-${{ matrix.php-version }}-${{ github.run_id }}
           path: "build"