Regex captures `url()`

[rdallasgray]

Hey -- the standard regex (https://github.com/vincentmac/gulp-fingerprint/blob/master/index.js#L22) uses the star operator to capture urls, which results in, e.g., url() being matched, with no capture group. That then causes a failure because the code here https://github.com/vincentmac/gulp-fingerprint/blob/master/index.js#L58 returns the match index, not the matched text.

This won't happen if you use the + operator instead.

Sorry I don't have time to create a PR or tests for this -- thought at least I could let you know.

[mvx24]

It looks like the standard regex also captures and removes hash fragments and query strings, which isn't desired in my case. The replace mode seems to work better for me.