Update minor version to 6.6.0

model/version.go

@@ -13,6 +13,7 @@ import (
 // It should be maintained in chronological order with most current
 // release at the front of the list.
 var versions = []string{
+	"6.6.0",
 	"6.5.0",
 	"6.4.0",
 	"6.3.0",