Replace node-source-map-resolve with node-css as the later package contains former.
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -6,7 +6,7 @@
 
 exports.extend = require('extend-shallow');
 exports.SourceMap = require('source-map');
-exports.sourceMapResolve = require('source-map-resolve');
+exports.sourceMapResolve = require('css');
 
 /**
  * Convert backslash in the given string to forward slashes
