使用Cloud Build从git进行连续部署

I am trying to make a build trigger for Cloud Run using this tutorial, but I get the following error message:

Starting Step #0
Step #0: Already have image (with digest): gcr.io/cloud-builders/docker
Step #0: unable to prepare context: unable to evaluate symlinks in Dockerfile path: lstat /workspace/Dockerfile: no such file or directory
Finished Step #0
ERROR
ERROR: build step 0 "gcr.io/cloud-builders/docker" failed: step exited with non-zero status: 1

有人知道为什么吗?