fix(package): update strip-ansi to version 5.2.0

Closes #84

Author: greenkeeper[bot]

package.json

@@ -64,7 +64,7 @@
     "request": "^2.76.0",
     "rimraf": "^2.5.4",
     "semver": "^5.3.0",
-    "strip-ansi": "^3.0.1",
+    "strip-ansi": "^5.2.0",
     "style-loader": "^0.13.1",
     "stylus": "^0.54.5",
     "stylus-loader": "^2.3.1",