Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/docs.yml

@@ -9,7 +9,7 @@ jobs:
     name: Docs Deployment
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v3
         with:
           cache: npm

.github/workflows/main.yml

@@ -29,7 +29,7 @@ jobs:
       - name: Set git safe directory
         run: |
           git config --global safe.directory '*'
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         env:
           TOKEN: "${{ github.event_name == 'push' && endsWith(github.ref, 'develop') && matrix.ros_distro == 'noetic' && secrets.RWT_BOT_PAT || github.token }}"
         with: