chore(deps): bump actions/checkout from 5 to 6 (#3)

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

Author: dependabot[bot]

.github/workflows/build.yaml

@@ -10,7 +10,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Find dependency list
         run: awk -f ./.github/scripts/extract_dependencies.awk README.md | tee apt-deps.txt
       - name: Cache apt packages

.github/workflows/formatting.yaml

@@ -10,7 +10,7 @@ jobs:
   check-formatting:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: clang-format -n -Werror src/*.c
       - run: clang-format -n -Werror include/**/*.h
       - run: clang-format -n -Werror nob.c