chore(deps): bump actions/upload-artifact from 4 to 6

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

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/validate.yml

@@ -16,7 +16,7 @@ jobs:
         node-version-file: '.nvmrc'
     - run: make validate.ci
     - name: Archive code coverage results
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v6
       with:
         name: code-coverage-report
         path: coverage/*.*