Bump actions/checkout from 4 to 6 in /.github/workflows

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

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

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
         node: ["18", "20", "22", "24"]
     name: Node.js ${{ matrix.node }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Setup node
         uses: actions/setup-node@v4
         with:

.github/workflows/release.yml

@@ -10,7 +10,7 @@ jobs:
       contents: read
       id-token: write
     steps:
-      - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # 4.1.7
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # 6.0.2
       - uses: actions/setup-node@1e60f620b9541d16bece96c5465dc8ee9832be0b # 4.0.3
         with:
           node-version: "22"