Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
         node-version: [16.x]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v4
         with:
@@ -48,7 +48,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: cache deps
         uses: actions/cache@main