Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v4...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] <support@github.com>

.github/workflows/build.yml

@@ -26,7 +26,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Install dependencies (Ubuntu)
       run: ./.github/scripts/install-dependencies-ubuntu.sh

.github/workflows/codeql-analysis.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
         # We must fetch at least the immediate parents so that if this is
         # a pull request then we can checkout the head.

.github/workflows/doxygen.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Install dependencies
       run: ./.github/scripts/install-dependencies-ubuntu.sh

.github/workflows/kernel.yml

@@ -20,7 +20,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Install kernel dependencies
       run: ./.github/scripts/install-kernel-dependencies.sh

.github/workflows/release.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install dependencies
         run: ./.github/scripts/install-dependencies-ubuntu.sh