Add className support to SelectButtonItems

[mann-david]

I'm submitting a ... (check one with "x")

[x ] bug report
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://forum.primefaces.org/viewforum.php?f=57

Current behavior
SelectButton does not use className from SelectItem API. Looking at the code, either this line

primereact/src/components/selectbutton/SelectButtonItem.js

Line 70 in dc52c5a

<div ref={(el) => this.el = el} className={className} onClick={this.onClick}>

or this line

primereact/src/components/selectbutton/SelectButtonItem.js

Line 71 in dc52c5a

<span className="p-button-text p-c">{this.props.label}</span>

should pull the className from the object defining the item. Neither does.

Expected behavior
CSS class specified via the SelectItem API should be applied

• React version:
  16.8.6

• PrimeReact version:
  Running 3.1.3, but checked source in Github for 3.2.1

[mertsincan]

Please try;

...
  {label: 'Apartment', value: 'Apartment', className: 'p-option-apartment'}