chore(deps): update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/main.yml

@@ -24,13 +24,13 @@ jobs:
         run: npm run lint
       - name: Run Playwright tests
         run: npm test
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         if: always()
         with:
           name: playwright-report
           path: playwright-report
           retention-days: 30
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         if: always()
         with:
           name: serenity-report