chore(package): update lockfile

https://npm.im/greenkeeper-lockfile

Author: greenkeeperio-bot

yarn.lock

@@ -6961,9 +6961,9 @@ strip-json-comments@~2.0.1:
   version "2.0.1"
   resolved "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-2.0.1.tgz#3c531942e908c2697c0ec344858c286c7ca0a60a"
 
-style-loader@^0.20.3:
-  version "0.20.3"
-  resolved "https://registry.npmjs.org/style-loader/-/style-loader-0.20.3.tgz#ebef06b89dec491bcb1fdb3452e913a6fd1c10c4"
+style-loader@^0.21.0:
+  version "0.21.0"
+  resolved "https://registry.npmjs.org/style-loader/-/style-loader-0.21.0.tgz#68c52e5eb2afc9ca92b6274be277ee59aea3a852"
   dependencies:
     loader-utils "^1.1.0"
     schema-utils "^0.4.5"