Add link to Changelog (#1397)

Summary:
Pull Request resolved: #1397

Added link to PR

Reviewed By: lorixx

Differential Revision: D18638528

fbshipit-source-id: 847deee505e4154a6940825a07ca24d664137c76

CHANGELOG.md

@@ -32,7 +32,7 @@ The changelog for `IGListKit`. Also see the [releases](https://github.com/instag
 
 - Created `IGListAdapterPerformanceDelegate` for IGListAdapter to be able to measure how long some operations take across all section controllers. For example, how long it takes to dequeue a cell. [Maxime Ollivier](https://github.com/maxoll) [(4662454)](https://github.com/Instagram/IGListKit/commit/4662454c4aedbc5d3bed0cb386f2ef93de40ba51)
 
-- Update CocoaPods integration to use the CocoaPods specs CDN [Koen Punt](https://github.com/koenpunt) (#1386)
+- Update CocoaPods integration to use the CocoaPods specs CDN [Koen Punt](https://github.com/koenpunt) [(#1386)](https://github.com/Instagram/IGListKit/pull/1386)
 
 - Remove useless system version code [Kinarobin](https://github.com/kinarobin) [(#1386)](https://github.com/Instagram/IGListKit/pull/1396)