Docker image build in Cluster (#327)

* * image build in cluster now
  use InitContainer to do the image building inside pods, which invoke
  docker again node's docker daemon
* create a docker build image tool fx/contrib/docker_packer
* clean up no need env in GitHub action workflow
* bump version

fx.go

@@ -15,7 +15,7 @@ import (
 	"github.com/urfave/cli"
 )
 
-const version = "0.7.4"
+const version = "0.7.5"
 
 var cfg *config.Config