Update dependency polished to v2.3.1

package.json

@@ -34,7 +34,7 @@
     "gatsby-plugin-typescript": "2.0.1",
     "gatsby-plugin-typography": "2.2.1",
     "normalize.css": "8.0.1",
-    "polished": "2.3.0",
+    "polished": "2.3.1",
     "react": "16.6.3",
     "react-chartjs-2": "2.7.4",
     "react-dom": "16.6.3",

yarn.lock

@@ -7597,10 +7597,10 @@ plyr@^3.3.21, plyr@^3.4.7:
     raven-js "^3.27.0"
     url-polyfill "^1.1.0"
 
-[email protected].0:
-  version "2.3.0"
-  resolved "https://registry.yarnpkg.com/polished/-/polished-2.3.0.tgz#66c8b66bc666e95d9d12d760dac9df758aed8f8e"
-  integrity sha512-G2yD9LhJy5HBuU+Im5qe70ubaJI/ZTTOIJO6GRMwJ2WSoAiPzlm8+LjAXMnm9/K0E0NumRVHvQu2HHPKQSYQjw==
+[email protected].1:
+  version "2.3.1"
+  resolved "https://registry.yarnpkg.com/polished/-/polished-2.3.1.tgz#557ea07e5bcb1b9c7d71935a01d0315831234d48"
+  integrity sha512-0mGyvVrHVRN92wfohriBWmMF4JLEnGgpZbpwPrNDhpB8NrX6lYI8GGWXEfrmrF+ZXg52Jkwd+D0rxViOvXM9RQ==
   dependencies:
     "@babel/runtime" "^7.0.0"