Update actions/checkout action to v6 (#63)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/actionlint.yml

@@ -19,7 +19,7 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Check workflow files
         uses: docker://rhysd/actionlint:latest
         with:

.github/workflows/checkov.yml

@@ -29,7 +29,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so follow-up steps can access it
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Checkov GitHub Action
         uses: bridgecrewio/checkov-action@v12

.github/workflows/claude-code-review.yml

@@ -30,7 +30,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 1
 

.github/workflows/claude.yml

@@ -29,7 +29,7 @@ jobs:
       actions: read # Required for Claude to read CI results on PRs
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 1
 

.github/workflows/github-pages.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
 #      - name: Generate your content
 #        run: echo "Optional placeholder. Put your project's static website generator command here."

.github/workflows/markdownlint.yml

@@ -15,7 +15,7 @@ jobs:
     permissions:
       contents: read
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: DavidAnson/markdownlint-cli2-action@v19
       with:
         globs: |