update changelog (imported from #1360)

Author: gregsdennis

jsonschema-core.md

@@ -3303,7 +3303,7 @@ to the document.
 
 ### draft-bhutton-json-schema-next
 - `contains` now applies to objects as well as arrays
-- Use IRIs instead of URIs
+- Use IRIs instead of URIs, including allowing unicode in plain-name fragments
 - Remove bookending requirement for `$dynamicRef`
 - Add `propertyDependencies` keyword