Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/test-secret-scan.yml

@@ -7,11 +7,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
           fetch-depth: 1
     - name: Checkout Test Data
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
         repository: trufflesecurity/test_keys
         path: test_keys

python-format/action.yml

@@ -9,7 +9,7 @@ jobs:
   run-formatter:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v5
         with:
           python-version: 3.13.3

python-lint/action.yml

@@ -9,7 +9,7 @@ jobs:
   run-linter:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v5
         with:
           python-version: 3.13.3