address comments

apigee_sync.go

diff --git a/apigee_sync.go b/apigee_sync.go
index 62088b0..80a00fa 100644
--- a/apigee_sync.go
+++ b/apigee_sync.go
@@ -93,7 +93,7 @@
 }
 
 func addHeaders(req *http.Request) {
-	req.Header.Add("Authorization", "Bearer "+tokenManager.getBearerToken())
+	req.Header.Set("Authorization", "Bearer "+tokenManager.getBearerToken())
 	req.Header.Set("apid_instance_id", apidInfo.InstanceID)
 	req.Header.Set("apid_cluster_Id", apidInfo.ClusterID)
 	req.Header.Set("updated_at_apid", time.Now().Format(time.RFC3339))