Bump node-sass from 4.5.3 to 4.6.1

Bumps [node-sass](https://github.com/sass/node-sass) from 4.5.3 to 4.6.1.
- [Release notes](https://github.com/sass/node-sass/releases?after=v4.7.0)
- [Changelog](https://github.com/sass/node-sass/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sass/node-sass/compare/v4.5.3...v4.6.1)

package.json

@@ -74,7 +74,7 @@
     "lolex": "^1.5.2",
     "mocha": "^4.0.1",
     "nightwatch": "^0.9.12",
-    "node-sass": "^4.5.2",
+    "node-sass": "^4.6.1",
     "opn": "^4.0.2",
     "optimize-css-assets-webpack-plugin": "^1.3.0",
     "ora": "^1.1.0",

yarn.lock

@@ -4201,9 +4201,9 @@ node-pre-gyp@^0.6.36:
     tar "^2.2.1"
     tar-pack "^3.4.0"
 
-node-sass@^4.5.2:
-  version "4.5.3"
-  resolved "https://registry.yarnpkg.com/node-sass/-/node-sass-4.5.3.tgz#d09c9d1179641239d1b97ffc6231fdcec53e1568"
+node-sass@^4.6.1:
+  version "4.6.1"
+  resolved "https://registry.yarnpkg.com/node-sass/-/node-sass-4.6.1.tgz#9b331cf943ee5440f199e858941a90d13bc9bfc5"
   dependencies:
     async-foreach "^0.1.3"
     chalk "^1.1.1"
@@ -4221,7 +4221,7 @@ node-sass@^4.5.2:
     node-gyp "^3.3.1"
     npmlog "^4.0.0"
     request "^2.79.0"
-    sass-graph "^2.1.1"
+    sass-graph "^2.2.4"
     stdout-stream "^1.4.0"
 
 "nopt@2 || 3", nopt@3.x, nopt@~3.0.1:
@@ -5336,7 +5336,7 @@ samsam@1.x, samsam@^1.1.3:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/samsam/-/samsam-1.2.1.tgz#edd39093a3184370cb859243b2bdf255e7d8ea67"
 
-sass-graph@^2.1.1:
+sass-graph@^2.2.4:
   version "2.2.4"
   resolved "https://registry.yarnpkg.com/sass-graph/-/sass-graph-2.2.4.tgz#13fbd63cd1caf0908b9fd93476ad43a51d1e0b49"
   dependencies: