build(deps): bump actions/checkout from 3.5.3 to 3.6.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 3.5.3 to 3.6.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3.5.3...v3.6.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/main.yaml

@@ -14,7 +14,7 @@ jobs:
     name: Build
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v3.5.3
+      - uses: actions/checkout@v3.6.0
         with:
           # intentionally don't set it to "recursive" as zsa's submodules are
           # managed via their Makefile.