Updated changelog.

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changes By Release
 
+## 5.2.0
+* Updates all core dependencies to the latest:
+  * `argparse`: `1.0.2` -> `1.0.7`
+  * `csswring`: `3.0.5` -> `4.2.2`
+  * `mincer`: `1.3.0` -> `1.4.1`
+  * `uglify-js: `2.4.23` -> `2.6.2`
+  * `postcss`: `5.0.19` (new dependency) 
+
 ## 5.1.1
 * Fix for compile=true ignoring already built asset (#322), thanks to @dapriett
-* Fix for serving source maps, thanks to @inukshuk
+* Fix for serving source maps, thanks to @inukshuk