Update CHANGELOG for beta 6

Author: garrettmoon

CHANGELOG.md

@@ -1,6 +1,8 @@
 ## master
 
 * Add your own contributions to the next release on the line below this with your name.
+
+## 3.0.1 -- Beta 6
 - [fix] Add some sane limits to the disk cache: [#201]https://github.com/pinterest/PINCache/pull/201
 - [new] Update enumeration methods to allow a stop flag to be flipped by caller: [#204](https://github.com/pinterest/PINCache/pull/204)
 - [performance] Improves cache miss performance by ~2 orders of magnitude on device: [#202](https://github.com/pinterest/PINCache/pull/202)