Merge pull request #157 from css-modules/greenkeeper-postcss-5.2.0

Update postcss to version 5.2.0 🚀

Author: geelen

package.json

@@ -8,7 +8,7 @@
  },
  "dependencies": {
  "icss-replace-symbols": "1.0.2",
- "postcss": "5.1.2",
+ "postcss": "5.2.0",
  "postcss-modules-values": "1.2.2",
  "postcss-modules-extract-imports": "1.0.0",
  "postcss-modules-local-by-default": "1.1.1",