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/check.yml

@@ -70,7 +70,7 @@ jobs:
           rustup_hash: 0b2f6c8f85a3d02fde2efc0ced4657869d73fccfce59defb4e8d29233116e6db
 
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # This step might be removed if the distro included a recent enough
       # version of NSS.  Ubuntu 20.04 only has 3.49, which is far too old.