Merge pull request #93 from sttts/sttts-codegen-1.16

hack/update-codegen.sh: add -mod=vendor to work with recent Golang

Merge pull request #75 from roycaihw/feat/healthz

add healthz to migrator and trigger

Merge pull request #66 from sttts/patch-1

Add myself to SECURITY_CONTACTS

Merge pull request #37 from caesarxuchao/cluster-scoped-migration-API

Cluster scoped migration API

Merge pull request #29 from caesarxuchao/add-metrics

Adding metrics for the core migrator