Fix typing issues on sub fields of template

[mathix420]

Expected behavior

myCurrentTemplate.username.check('my-new-username');

Current behavior

import { VTemplateRow } from 'vuito/types';

(<VTemplateRow>myCurrentTemplate.username).check('my-new-username');

Line causing the issue (in src/template.ts)

export class Template {
  [key: string]: VTemplateRow | VTemplate['check'];
  // ...
}

[mathix420]

Fxed on v2.0.1