chore: update actions/checkout action to v6

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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - name: Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v2
         with:
@@ -78,7 +78,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 60
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - name: Use Node.js 16
         uses: actions/setup-node@v2
         with:
@@ -95,7 +95,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 60
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Use Node.js 16