v3 refactor (#1868)

* Move to v3

Co-authored-by: Ben Toogood <bentoogood@gmail.com>

event.go

@@ -1,16 +0,0 @@
-package micro
-
-import (
-	"context"
-
-	"github.com/micro/go-micro/v2/client"
-)
-
-type event struct {
-	c     client.Client
-	topic string
-}
-
-func (e *event) Publish(ctx context.Context, msg interface{}, opts ...client.PublishOption) error {
-	return e.c.Publish(ctx, e.c.NewMessage(e.topic, msg), opts...)
-}