update changelog

CHANGELOG.md

@@ -4,9 +4,12 @@
 	- filter histogram: replaces bit.ly's data_hacks with a built-in AWK program to calculate a histogram. May not be entirely portable @hexylena.
 	- mutate scale-table-autovacuum: Dynamically update autovacuum and autoanalyze scale for large tables. @natefoo
 	- query tools-usage-per-month from @lldelisle
+- Updated:
+	- query monthly-cpu-stats to add --nb_users --filter_email by @lldelisle
 - Fixed:
 	- Replaced hardcoded metric_name with the variable in query_tool-metrics function @sanjaysrikakulam
 	- improved man pages a tad
+	- fixed query monthly-cpu-stats when year was specified
 
 # 21