Adds CHANGELOG entry for #349 and release 2.0.3

Author: weierophinney

CHANGELOG.md

@@ -2,6 +2,29 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
+## 2.0.3 - 2019-01-05
+
+### Added
+
+- Nothing.
+
+### Changed
+
+- Nothing.
+
+### Deprecated
+
+- Nothing.
+
+### Removed
+
+- Nothing.
+
+### Fixed
+
+- [#349](https://github.com/zendframework/zend-diactoros/pull/349) fixes an issue when marshaling headers with values of `0` or `0` from the
+  SAPI, ensuring they are detected and injected into the ServerRequest properly.
+
 ## 2.0.2 - 2018-12-20
 
 ### Added