Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/check-external-links.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Python 3.12
       uses: actions/setup-python@v6
       with:

.github/workflows/headers-generate-json-files.yml

@@ -11,7 +11,7 @@ jobs:
     permissions:
       contents: write    
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Python 3.12
       uses: actions/setup-python@v6
       with:

.github/workflows/monitoring-oshp-site-references.yml

@@ -11,7 +11,7 @@ jobs:
   build:
     runs-on: ubuntu-latest   
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Python 3.12
       uses: actions/setup-python@v6
       with:

.github/workflows/monitoring-technical-references-generate-dashboard.yml

@@ -13,7 +13,7 @@ jobs:
     permissions:
       contents: write    
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Python 3.12
       uses: actions/setup-python@v6
       with:

.github/workflows/tab-stats-headers-generate-related-files.yml

@@ -15,7 +15,7 @@ jobs:
     permissions:
       contents: write    
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Python
       uses: actions/setup-python@v6
       with:

.github/workflows/validate-owasp-metadata.yaml

@@ -21,7 +21,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Validate metadata file
         uses: owasp/nest-schema/.github/actions/validate@1a0eadfe9ba7b7a359ba08e77b98ce285305fd63