Revert "fix: use master branch when build docker image"

This reverts commit c63ba547.

.github/workflows/docker.yml

@@ -13,8 +13,6 @@ jobs:
     steps:
       - name: Check out the repo
         uses: actions/checkout@v2
-        with:
-          ref: master
       - name: Docker meta
         id: meta
         uses: docker/metadata-action@v3