Create isValidURN and isValidURI and use isValidURI everywhere where it is needed

person.go

@@ -29,7 +29,7 @@ func (p *Person) Check() error {
 	}
 
 	if p.URI != "" {
-		if !isValidURL(p.URI) {
+		if !isValidURI(p.URI) {
 			return fmt.Errorf("uri element of person %v not correctly formatted", p.Name)
 		}
 	}