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](actions/checkout@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>

Author: dependabot[bot]

.github/workflows/build-and-test-via-cmake.yml

@@ -11,7 +11,7 @@ jobs:
   clang-format:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: DoozyX/clang-format-lint-action@v0.17
         with:
           source: '.'
@@ -66,7 +66,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     name: ${{ matrix.job-name }}
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: seanmiddleditch/gha-setup-ninja@v4
       if: contains(matrix.generator, 'Ninja')
 

.github/workflows/build-and-test-visual-studio-solutions.yml

@@ -13,7 +13,7 @@ jobs:
   build_visual_studio_sln:
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: create project
         run: |