Bump actions/checkout from 2.4.0 to 3.0.2 (#645)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.4.0 to 3.0.2.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2.4.0...v3.0.2)

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

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

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

.github/workflows/build.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-18.04
     steps:
     # checkout to the commit that has been pushed
-    - uses: actions/checkout@v2.4.0
+    - uses: actions/checkout@v3.0.2
       with:
         submodules: true  # Fetch Hugo themes (true OR recursive)
         fetch-depth: 0    # Fetch all history for .GitInfo and .Lastmod