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

Author: renovate[bot]

.github/workflows/gh-pages.yml

@@ -8,7 +8,7 @@ jobs:
   deploy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0    # full history for contributor information
       - name: Setup Node

.github/workflows/test.yml

@@ -5,7 +5,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Setup Node