Update readme

Apply CRI to support CRI-O

support KUBECONFIG env

Update README.md

Specify cnsenter pod container name when fetching

This is necessary in some setup like environement with Istio in which sidecar containers are automatically added to the pod

Fix krew.yaml

Add github action for release krew

Add github action for release krew

Update usage and example for kubectl plugin mode

Rollback goreleaser