v 1.2.8

Feature:

1. support nested value in item and header value with '.' character.
   e.g.

// before:
const headers: Header[] = [
    { text: 'Name', value: 'name' },
    { text: 'Height', value: 'height' },
    { text: 'Weight', value: 'weight' },
    ...
];

const items: Item[] = [
  { name: 'AA', height: '6-2', weight: 185 }
 ...        
];

// after:
const headers: Header[] = [
    { text: 'Name', value: 'name' },
    { text: 'Height', value: 'info.height' },
    { text: 'Weight', value: 'info.weight' },
    ...
];
const items: Item[] = [
  { name: 'AA', info: { height: '6-2', weight: 185 } },
 ...        
];