chore(changelog): add logging feature

CHANGELOG.md

@@ -6,7 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 * Plugins don't crash zellij anymore on receiving mouse events (https://github.com/zellij-org/zellij/pull/620)
-
+* A universal logging system has been implemented (https://github.com/zellij-org/zellij/pull/592)
+  * Added [`log`](https://docs.rs/log/0.4.14/log/#macros) crate support for logging within Zellij
+  * Messages sent over the `stderr` of plugins are now logged as well, bringing back `dbg!` support!
 
 ## [0.15.0] - 2021-07-19
 * Kill children properly (https://github.com/zellij-org/zellij/pull/601)