support pipe for omit and pick

[universam1]

It was surprising to me to learn that omit and pick do not support a pipe signature, as it reads natural to me.

{{- range $key, $value := include "myConf" . | fromYaml | omit "somekey" -}}
{{- dict "one" 1 "two" 222222 | pick "two" -}}

Instead it errors out

can't handle "xy" for arg of type map[string]interface {}