ci: bump actions/checkout from v2.3.0 to v2.3.1 (#355)

Bumps [actions/checkout](https://github.com/actions/checkout) from v2.3.0 to v2.3.1.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/master/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2.3.0...28c7f3d2b5162b5ddd3dfd9a45aa55eaf396478b)

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

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

.github/workflows/dev-image.yml

@@ -31,7 +31,7 @@ jobs:
     runs-on: ubuntu-18.04
     if: contains(github.event.head_commit.message, '[skip ci]') == false
     steps:
-      - uses: actions/checkout@v2.3.0
+      - uses: actions/checkout@v2.3.1
       - run: make build
       - run: make cirun cmd="npm ci"
       - run: make ciall