update changelog

Author: rikashore

CHANGELOG.md

@@ -10,6 +10,7 @@
   working with functions in pipelines.
 - Fixed a bug where `regex.scan` would not work correctly on utf8.
 - The performance of `list.flatten` has been greatly improved.
+- The `string_builder` module gains the `join` function.
 
 ## v0.24.0 - 2022-10-15