Update datasource.go

Co-authored-by: Julien Duchesne <julienduchesne@live.com>

Author: wanieldilson

datasource.go

@@ -9,7 +9,7 @@ import (
 // DataSource represents a Grafana data source.
 type DataSource struct {
 	ID     int64  `json:"id,omitempty"`
-	UID    string `json:"uid"`
+	UID    string `json:"uid,omitempty"`
 	Name   string `json:"name"`
 	Type   string `json:"type"`
 	URL    string `json:"url"`