fix: miss checkout in ci workflow (#634)

Signed-off-by: Bob Du <i@bobdu.cc>

Author: BobDu

.github/workflows/build_docker.yml

@@ -39,6 +39,9 @@ jobs:
             os: ubuntu-24.04-arm
     runs-on: ${{ matrix.os }}
     steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
       - name: Prepare
         run: |
           platform=${{ matrix.platform }}