restore: ignore created_unix for milestone table (#5264)

models/models.go

@@ -301,6 +301,7 @@ func ImportDatabase(dirPath string, verbose bool) (err error) {
 
 	skipInsertProcessors := map[string]bool{
 		"mirror":    true,
+		"milestone": true,
 	}
 
 	// Purposely create a local variable to not modify global variable