Update Changelog: ghttp can handle requests concurrently

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cfbde1f..faad006 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - `Ω`, `Expect`, `Eventually`, and `Consistently` now immediately `panic` if there is no registered fail handler.  This is always a mistake that can hide failing tests.
 - `Receive()` no longer errors when passed a closed channel, it's perfectly fine to attempt to read from a closed channel so Ω(c).Should(Receive()) always fails and Ω(c).ShoudlNot(Receive()) always passes with a closed channel.
 - Added `HavePrefix` and `HaveSuffix` matchers.
+- `ghttp` can now handle concurrent requests.
 
 ## 1.0 (8/2/2014)