drop AuthTLS option and use client TLSConfig option

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

options.go

@@ -3,7 +3,6 @@ package grpc
 
 import (
 	"context"
-	"crypto/tls"
 
 	"github.com/unistack-org/micro/v3/client"
 	"google.golang.org/grpc"
@@ -72,16 +71,6 @@ func Codec(contentType string, c encoding.Codec) client.Option {
 	}
 }
 
-// AuthTLS should be used to setup a secure authentication using TLS
-func AuthTLS(t *tls.Config) client.Option {
-	return func(o *client.Options) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, tlsAuth{}, t)
-	}
-}
-
 //
 // MaxRecvMsgSize set the maximum size of message that client can receive.
 //