update changelog

changelog.md

@@ -2,6 +2,9 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.51] - 2023-03-08
+- Changed panel selections to use `max` rather than `mean` with `$__interval`
+
 ## [0.50] - 2023-03-08
 - Changed group by size from '5m' to '$__interval' globally