docs: add "Breaking Changes " section to Changelog

Author: kanutocd

CHANGELOG.md

@@ -47,6 +47,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Broken links in README fixed.
 - Development environment setup guide added.
 
+### ⚠️ Breaking Changes
+
+- `pg`, `trilogy`, and `bigdecimal` are no longer runtime dependencies. If your
+  application relies on them being pulled in transitively via `whodunit-chronicles`,
+  add them explicitly to your own Gemfile.
+- remove ruby@3.1 from the supported versions of Ruby
+
 ## [0.2.0] - 2025-01-28
 
 ### Added