Add v1.3.0 to changelog (#417)

* Add v1.3.0 to changelog

* Reword slightly

CHANGELOG.md

@@ -1,5 +1,16 @@
 # Changelog
 
+## v1.3.0 (25 Apr 2017)
+
+This release adds an enhancement to zap's testing helpers as well as the
+ability to marshal an AtomicLevel. It is fully backward-compatible.
+
+Enhancements:
+
+* [#415][]: Add a substring-filtering helper to zap's observer. This is
+  particularly useful when testing the `SugaredLogger`.
+* [#416][]: Make `AtomicLevel` implement `encoding.TextMarshaler`.
+
 ## v1.2.0 (13 Apr 2017)
 
 This release adds a gRPC compatibility wrapper. It is fully backward-compatible.
@@ -187,3 +198,5 @@ upgrade to the upcoming stable release.
 [#396]: https://github.com/uber-go/zap/pull/396
 [#386]: https://github.com/uber-go/zap/pull/386
 [#402]: https://github.com/uber-go/zap/pull/402
+[#415]: https://github.com/uber-go/zap/pull/415
+[#416]: https://github.com/uber-go/zap/pull/416