adapt and optimise Dockerfile

2 jobs for 1-end-support-for-directly-deploying-k8s-manifests in 2 minutes and 11 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
passed #101878
test

00:00:51

 
  Publish
passed #101879
mbr
build-feature-branch-image

00:01:20