Update CHANGELOG

Author: sdboyer

CHANGELOG.md

@@ -27,6 +27,7 @@ IMPROVEMENTS:
 * Hash digests of vendor contents are now stored in `Gopkg.lock`, and the contents of vendor are only rewritten on change or hash mismatch ([#1912](https://github.com/golang/dep/pull/1912)).
 * Don't exclude `Godeps` folder ([#1822](https://github.com/golang/dep/issues/1822)).
 * Add project-package relationship graph support in graphviz ([#1588](https://github.com/golang/dep/pull/1588)).
+* Limit concurrency of `dep status` to avoid hitting open file limits ([#1923](https://github.com/golang/dep/issue/1923)).
 
 WIP:
 * Enable importing external configuration from dependencies during init (#1277). This is feature flagged and disabled by default.