1. deprecate vela install and introduce helm install to install vela core helm chart https://artifacthub.io/packages/helm/kubevela/vela-core
2. allow TraitDefinition/WorkloadDefinition without spec.definitionRef #1001 #991
3. support legacy K8s cluster version(1.14~1.15) and automatically generate helm chart for these user #983
4. fix duplicate image push in vela cli #1012
5. move template out from extension to spec.template, now template is a formalized field of Definition #1014
6. implement Apply Once Only Force for special use case #838
7. support status loop back mechanism for health check and custom status message #975