Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/main.yml

@@ -10,7 +10,7 @@ jobs:
       # CI: false
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v4