missing checkout action

Author: travisghansen

.github/workflows/docker_image.yml

@@ -22,6 +22,8 @@ jobs:
         with:
           access_token: ${{ github.token }}
 
+      - uses: actions/checkout@v2
+
       - name: docker build
         run: |
           export ARCH=$([ $(uname -m) = "x86_64" ] && echo "amd64" || echo "arm64")