Update actions/checkout action to v6 (#145)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/lint.yml

@@ -8,7 +8,7 @@ jobs:
         # https://nodejs.org/en/about/releases/
         node-version: ['18', '20']
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: actions/setup-node@v6
       with:
         node-version: ${{ matrix.node-version }}