Update actions/checkout action to v6 (#60)

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

Author: renovate[bot]

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
         node-version: [12.x]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v6
         with: