Bump actions/checkout action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -48,7 +48,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 
@@ -107,7 +107,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Download artifacts
         uses: actions/download-artifact@v6
         with: