changelog: update for 7.3.0 (#28602)

CHANGELOG.md

+# 7.3.0 (2020-10-28)
+
+  ### Features / Enhancements
+  * **AzureMonitor**: Support decimal (as float64) type in analytics/logs. [#28480](https://github.com/grafana/grafana/pull/28480), [@kylebrandt](https://github.com/kylebrandt)
+  * **Plugins signing**: UI information. [#28469](https://github.com/grafana/grafana/pull/28469), [@dprokop](https://github.com/dprokop)
+  * **Short URL**: Update last seen at when visiting a short URL. [#28565](https://github.com/grafana/grafana/pull/28565), [@marefr](https://github.com/marefr)
+  
+  ### Bug Fixes
+  * **Alerting**: Log warnings for obsolete notifiers when extracting alerts and remove frequent error log messages. [#28162](https://github.com/grafana/grafana/pull/28162), [@papagian](https://github.com/papagian)
+  * **Auth**: Fix SigV4 request verification step for Amazon Elasticsearch Service. [#28481](https://github.com/grafana/grafana/pull/28481), [@wbrowne](https://github.com/wbrowne)
+  * **Auth**: Should redirect to login when anonymous enabled and URL with different org than anonymous specified. [#28158](https://github.com/grafana/grafana/pull/28158), [@marefr](https://github.com/marefr)
+  * **Elasticsearch**: Fix handling of errors when testing data source. [#28498](https://github.com/grafana/grafana/pull/28498), [@marefr](https://github.com/marefr)
+  * **Graphite**: Fix default version to be 1.1. [#28471](https://github.com/grafana/grafana/pull/28471), [@ivanahuckova](https://github.com/ivanahuckova)
+  * **StatPanel**: Fixes BizChart error max: yyy should not be less than min zzz. [#28587](https://github.com/grafana/grafana/pull/28587), [@hugohaggmark](https://github.com/hugohaggmark)
+
+
 # 7.3.0-beta2 (2020-10-22)
 
 ### Features / Enhancements