Add entry to CHANGELOG

Author: garrettmoon

CHANGELOG.md

@@ -3,6 +3,7 @@
 * Add your own contributions to the next release on the line below this with your name.
 - [fix] Add some sane limits to the disk cache: [#201]https://github.com/pinterest/PINCache/pull/201
 - [performance] Improves cache miss performance by ~2 orders of magnitude on device: [#202](https://github.com/pinterest/PINCache/pull/202)
+- [performance] Significantly improve startup performance: [#203](https://github.com/pinterest/PINCache/pull/203)
 
 ## 3.0.1 -- Beta 5
 - [fix] Respect small byteLimit settings by checking object size in setObject: [#198](https://github.com/pinterest/PINCache/pull/198)