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

Author: renovate[bot]

.github/workflows/publish.yml

@@ -21,7 +21,7 @@ jobs:
       contents: write
       id-token: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ssh-key: ${{ secrets.DEPLOY_KEY }}
       - name: Check if on main branch

.github/workflows/verify.yml

@@ -13,7 +13,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v6
         with:
           node-version: lts/*