Bump actions/checkout from 2 to 2.3.4 (#98)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 2.3.4.
- [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...v2.3.4)

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

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

.github/workflows/ci.yaml

@@ -36,7 +36,7 @@ jobs:
     - name: Set artifact name
       run: echo "name=ashirt-${{ needs.store-sha8.outputs.sha8 }}-$(uname -s | tr '[:upper:]' '[:lower:]')" >> $GITHUB_ENV
     - name: Check out code
-      uses: actions/checkout@v2 
+      uses: actions/checkout@v2.3.4 
       with:
         submodules: true