Upgrade PrettyCSS to latest

Roan’s changes are in the latest release, so we can use it.

Author: Mat Brown

package.json

@@ -146,7 +146,7 @@
   "bugs": "https://trello.com/b/ONaFg6wh/popcode",
   "license": "MIT",
   "dependencies": {
-    "PrettyCSS": "fidian/PrettyCSS#3516dfa69",
+    "PrettyCSS": "^0.3.17",
     "array-to-sentence": "^2.0.0",
     "bowser": "^1.4.5",
     "brace": "^0.11.0",

yarn.lock

@@ -213,9 +213,9 @@ JSONStream@^1.0.3, JSONStream@^1.0.4:
     jsonparse "^1.2.0"
     through ">=2.2.7 <3"
 
-PrettyCSS@fidian/PrettyCSS#3516dfa69:
-  version "0.3.16"
-  resolved "https://codeload.github.com/fidian/PrettyCSS/tar.gz/3516dfa6995869c3550541b1fe70b1a56209245e"
+PrettyCSS@^0.3.17:
+  version "0.3.17"
+  resolved "https://registry.yarnpkg.com/PrettyCSS/-/PrettyCSS-0.3.17.tgz#46ab47815220e5e6dc45f74ace27a5cf63d3f5a6"
   dependencies:
     option-parser "~1.0.0"