Add CHANGELOG for v0.20 (#345)

Co-authored-by: Ved misra <47312748+misraved@users.noreply.github.com>

CHANGELOG.md

@@ -1,4 +1,10 @@
-## v0.19 [2024-04-06]
+## v0.20 [2024-03-27]
+
+_Bug fixes_
+
+- Fixed the `ecs_cluster_active_service_count` query in the `AWS ECS Cluster Dashboard` to correctly return the count of `Cluster Active Services` instead of `ECS Clusters`. ([#341](https://github.com/turbot/steampipe-mod-aws-insights/pull/341)) (Thanks [@mupi2k](https://github.com/mupi2k) for the contribution!)
+
+## v0.19 [2024-03-06]
 
 _Powerpipe_