Note performance improvements from #193 in changelog

Author: jmurty

CHANGELOG.md

@@ -34,6 +34,11 @@ system, you must also run the `--upgrade` command in each repository:
 
 ## [Unreleased]
 
+### Changed
+
+- Greatly improve performance in a repository with many files for pre-commit
+  safety check, encrypted file listing, and showing raw file (#193)
+
 ### Fixed
 
 - Fix pre-commit hook to use "fast" multi-threaded mode for Bash versions 5+ as