Bump actions/checkout from 1 to 4 in the github-actions group

Bumps the github-actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `actions/checkout` from 1 to 4
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v1...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/cpplint_modified_files.yml

@@ -11,7 +11,7 @@ jobs:
   cpplint_modified_files:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1  # v1, NOT v2 or v3 or v4
+      - uses: actions/checkout@v4  # v1, NOT v2 or v3 or v4
       - uses: actions/setup-python@v5
         with:
           python-version: 3.x