chore(deps): bump actions/checkout from 2 to 3

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3)

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

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

.github/workflows/test.yml

@@ -29,6 +29,6 @@ jobs:
       with:
         version: ${{ matrix.emacs_version }}
 
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Check startup
       run: ./test-startup.sh