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-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

.github/workflows/linux.yml

@@ -9,7 +9,7 @@ jobs:
     if: "!contains(github.event.head_commit.message, '[ci skip]') && !contains(github.event.head_commit.message, '[skip ci]')"
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Build
         run: docker run --rm -e WORK_DIR=$PWD -v $PWD:$PWD ubuntu:24.04 $PWD/.github/workflows/linux.sh