Bump actions/checkout from 3 to 4 (#29)

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

.github/workflows/ci-build.yml

@@ -19,7 +19,7 @@ jobs:
     outputs:
       head: ${{ steps.head.outputs.head }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           # Check out the branch that the PR refers to, so the git HEAD isn't detached.
           ref: ${{ github.event.pull_request.head.ref }}
@@ -48,7 +48,7 @@ jobs:
       statuses: write
     needs: [format]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           # Check out the HEAD from the previous workflow, to catch any mistakes that the formatter
           # may have introduced.

.github/workflows/deploy.yml

@@ -11,7 +11,7 @@ jobs:
     name: Deploy to GitHub Pages
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
           node-version: 18