Add changelog for 1.5.0. (#164)

CHANGELOG.md

@@ -1,3 +1,13 @@
+# 1.5.0
+ * Add pluggable name resolution. Users can now override the IP addresses for
+   hostnames of their choice (#148).
+ * bugfix: Don't re-pool streams on drop. This would occur if the user called
+   `response.into_reader()` and dropped the resulting `Read` before reading all
+   the way to EOF. The result would be a BadStatus error on the next request to
+   the same hostname. This only affected users using an explicit Agent (#160).
+ * Automatically set Transfer-Encoding: chunked when using `send` (#86).
+ * `into_reader()` now returns `impl Read + Send` instead of `impl Read` (#156).
+
 # 1.4.1
 
  * Use buffer to avoid byte-by-byte parsing result in multiple syscalls.