message: types definition : 'validate' name param is optional
  Got a small error using Typescript, the [`validate`](https://baianat.github.io/vee-validate/api/validator.html#api) method's `name` param is supposed to be optional
diff: @@ -158,7 +158,7 @@ export class Validator {
  localize(rootDictionary?: Object) :void;
  localize(language: string, dictionary?: Object) :void;
  setStrictMode(strictMode?: boolean): void;
  - validate(name: string, value?: any, scope?: string, silent?: boolean): Promise<any>;
  + validate(name?: string, value?: any, scope?: string, silent?: boolean): Promise<any>;
  validateAll(values?: Object, scope?: string, silent?: boolean): Promise<any>;
  validateScopes(silent?: boolean): Promise<any>;
  verify(value: any, rules: string|Object, options?: VerifyOptions): Promise<VerifyResult>;
  