Update DefaultPortModel.ts

when making custom port with custom styled link, I need to make a custom port model, which need a custom type in constructor, but options.type is missing in the DefaultPortModel constructor props type. 
So I added it in.

Author: lancety

packages/react-diagrams-defaults/src/port/DefaultPortModel.ts

@@ -11,6 +11,7 @@ import { AbstractModelFactory, DeserializeEvent } from '@projectstorm/react-canv
 export interface DefaultPortModelOptions extends PortModelOptions {
 	label?: string;
 	in?: boolean;
+	type?: string;
 }
 
 export interface DefaultPortModelGenerics extends PortModelGenerics {