chore(deps): update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/main.yaml

@@ -5,7 +5,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Use Node.js 20
       uses: actions/setup-node@v4
       with: