Bump actions/checkout from 2 to 3 (Gallopsled#2248)

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -221,7 +221,7 @@ jobs:
     if: github.repository_owner == 'Gallopsled' && github.event_name == 'push' && startsWith(github.event.ref, 'refs/heads/') && endsWith(github.event.ref, '-staging')
     needs: test
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         fetch-depth: 20
     - name: Push changes to protected branch