Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/pages.yml

@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: Use Node.js 18.x (LTS)
         uses: actions/setup-node@v4
         with:

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: Use Node.js 18.x (LTS)
         uses: actions/setup-node@v4
         with: