Bump actions/checkout from 5 to 6 (#368)

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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build-linux.yml

@@ -11,7 +11,7 @@ jobs:
       runs-on: ${{ matrix.os }}
       steps:
         - name: Checkout repository
-          uses: actions/checkout@v5
+          uses: actions/checkout@v6
 
         - name: Install dependencies
           run: |

.github/workflows/build-windows.yml

@@ -11,7 +11,7 @@ jobs:
       runs-on: ${{matrix.os}}
       steps:
         - name: Checkout repository
-          uses: actions/checkout@v5
+          uses: actions/checkout@v6
 
         - name: Install dependencies
           run: |

.github/workflows/check-crlf.yml

@@ -12,7 +12,7 @@ jobs:
 
     steps:
       - name: Checkout repository contents
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Use action to check for CRLF endings
         uses: erclu/check-crlf@master