build(deps): bump actions/checkout from 2 to 3 (#62)

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

.github/workflows/containers.yml

@@ -97,7 +97,7 @@ jobs:
           cache-to: type=gha,mode=max
 
       - name: Checkout nimskull
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: nim-works/nimskull
           ref: ${{ env.nimskull_test_commit }}