FIX(ci): use busybox shell path in crane container

- Change shell path from /bin/sh to /busybox/sh
- Crane debug image uses busybox-based shell

.gitea/workflows/build-push.yaml

@@ -44,7 +44,7 @@ jobs:
                 containers:
                 - name: crane
                   image: gcr.io/go-containerregistry/crane:debug
-                  command: ["/bin/sh", "-c"]
+                  command: ["/busybox/sh", "-c"]
                   args:
                   - |
                     echo "Pushing image to ${REGISTRY}/${IMAGE_NAME}..."