[augmentations] Update changelog.

Author: munificent

working/augmentation-libraries/feature-specification.md

@@ -1,6 +1,6 @@
 # Augmentation Libraries
 
-Author: [email protected], Version: 1.3 (see [Changelog](#Changelog) at end)
+Author: [email protected], Version: 1.4 (see [Changelog](#Changelog) at end)
 
 Augmentation libraries allow splitting a Dart library into files. Unlike part
 files, each augmentation has its [own imports][part imports] and top-level
@@ -721,6 +721,11 @@ tools.
 
 ## Changelog
 
+### 1.4
+
+*   When inferring the type of a variable, only the original variable's
+    initializer is used.
+
 ### 1.3
 
 *   Constructor and function augmentations can't define default values.