gulp-css-cache-bust 
Transforms the path of
url()
to relative or absolute
Install
$ npm install --save-dev gulp-css-url
Usage
var gulp = ;var url = ; gulp;
API
url(options)
options.mode
Type: string
Default: 'relative'
The mode of transform. When 'absolute'
is specified, this plugin transforms the path of url to absolute.
options.base
Type: string
Default: '.'
The path of document root.