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

Author: renovate[bot]

.github/workflows/build-verify.yml

@@ -13,7 +13,7 @@ jobs:
     name: Test docs build
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v4
         with:
           node-version: 20

.github/workflows/codeql-analysis.yml

@@ -30,7 +30,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/gh-pages-deploy.yml

@@ -15,7 +15,7 @@ jobs:
     name: Deploy to GitHub Pages
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v4
         with:
           node-version: 20

.github/workflows/verify_cla_signature_pr.yml

@@ -21,7 +21,7 @@ jobs:
         python-version: [3.8]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 100
       - name: Set up Python ${{ matrix.python-version }}