build(deps): bump actions/checkout from 4 to 6

dependabot[bot]

24.37.2026 5461db15a50e43a6c133fd573b77d7a2d4c2c5eb

 .github/workflows/quickstart.yml

@@ -19,7 +19,7 @@

    steps:
      - name: Check out repository
        uses: actions/checkout@v4
        uses: actions/checkout@v6
        with:
          submodules: false