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-links.yml

@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           submodules: true
           fetch-depth: 0

.github/workflows/codeql-analysis.yml

@@ -35,7 +35,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/java8-maven.yml

@@ -19,7 +19,7 @@ jobs:
 
     steps:
       - name: Checkout source code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           submodules: true
           fetch-depth: 0
@@ -80,7 +80,7 @@ jobs:
 
     steps:
       - name: Checkout source code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           submodules: true
           fetch-depth: 0
@@ -130,7 +130,7 @@ jobs:
 
     steps:
       - name: Checkout source code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           submodules: true
           fetch-depth: 0