Add resourceQuery support

What's new ?

Features

1. Added support for passing options using resourceQuery. That allows following syntax:

     .selector {
       background-image: url(../../assets/ticket.svg?encoding=base64);
     } 

   Thanks to @c0defre4k for reporting this! Sorry for being so late.
2. Added more detailed usage examples to the readme.

Internal changes

1. upgraded devDependencies
2. refactor tests to follow DRY principle
3. make tests pass on both webpack 4 and 5

v7.0.0...v7.1.0