build(deps): bump actions/checkout from 4 to 6 (#61768)

Bump actions/checkout from 4 to 6.\n\nThanks @dependabot.

.github/workflows/docs-sync-publish.yml

@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 

.github/workflows/parity-gate.yml

@@ -48,7 +48,7 @@ jobs:
       OPENCLAW_LIVE_SETUP_TOKEN_VALUE: ""
     steps:
       - name: Checkout PR
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install pnpm
         uses: pnpm/action-setup@v4