Changelog.md in unparser-0.3.0 vs Changelog.md in unparser-0.4.0

@@ -1,4 +1,9 @@
+# v0.4.0 2018-12-01
+
+* Change to modern AST format.
+* Add experimental `Unparser.{parser,parse,parse_with_comments}`
+
 # v0.3.0 2018-11-16
 
 * Drop support for Ruby < 2.5
 
 # v0.2.7 2018-07-18