use metadata.Metadata (#8)

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

debug/log/kubernetes/kubernetes.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/unistack-org/micro/v3/debug/log"
+	"github.com/unistack-org/micro/v3/metadata"
 	"github.com/unistack-org/micro/v3/util/kubernetes/client"
 )
 
@@ -89,7 +90,7 @@ func (k *klog) parse(line string) log.Record {
 	if err := json.Unmarshal([]byte(line), &record); err != nil {
 		record.Timestamp = time.Now().UTC()
 		record.Message = line
-		record.Metadata = make(map[string]string)
+		record.Metadata = metadata.New(1)
 	}
 
 	record.Metadata["service"] = k.Options.Name

debug/log/log.go

@@ -5,6 +5,8 @@ import (
 	"encoding/json"
 	"fmt"
 	"time"
+
+	"github.com/unistack-org/micro/v3/metadata"
 )
 
 var (
@@ -29,7 +31,7 @@ type Record struct {
 	// Timestamp of logged event
 	Timestamp time.Time `json:"timestamp"`
 	// Metadata to enrich log record
-	Metadata map[string]string `json:"metadata"`
+	Metadata metadata.Metadata `json:"metadata"`
 	// Value contains log entry
 	Message interface{} `json:"message"`
 }