chore(deps): Bump actions/upload-artifact from 5 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/springwolf-plugins.yml

@@ -73,7 +73,7 @@ jobs:
         run: ./gradlew -p springwolf-examples/e2e pnpm_run_install_deps test
         env:
           SPRINGWOLF_EXAMPLE: ${{ matrix.plugin }}
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         if: always()
         with:
           name: test-plugin-${{ matrix.plugin }}-playwright