docs: add changelog for v1.5.0 and v1.6.0

CHANGELOG.md

@@ -1,3 +1,27 @@
+## v1.6.0
+
+### Feat
+
+- add notification delay
+
+### Fix
+
+- remove null variables from excluded_tags in notification rules
+- show correct count of notification history and fix pagination of notification history
+
+## v1.5.1
+
+### Feat
+
+- add bulk note for alerts
+- add excluded tags for notification rules
+- add search for history view
+
+### Fix
+
+- remove/hide forbidden actions
+- fix handling of actions in alerta ISA 18 2 alarm model
+
 ## v1.5.0
 
 ### Feat