Changelog update - 7.3.1 (#28699)

* Changelog update

* Update CHANGELOG.md

* Update CHANGELOG.md

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

CHANGELOG.md

+# 7.3.1 (2020-10-30)
+
+  ### Bug Fixes
+  * **Cloudwatch**: Fix duplicate metric data. [#28642](https://github.com/grafana/grafana/pull/28642), [@zoltanbedi](https://github.com/zoltanbedi)
+  * **Loki**: Fix error when some queries return zero results. [#28645](https://github.com/grafana/grafana/pull/28645), [@ivanahuckova](https://github.com/ivanahuckova)
+  * **PanelMenu**: Fix panel submenu not being accessible for panels close to the right edge of the screen. [#28666](https://github.com/grafana/grafana/pull/28666), [@torkelo](https://github.com/torkelo)
+  * **Plugins**: Fix descendent frontend plugin signature validation. [#28638](https://github.com/grafana/grafana/pull/28638), [@wbrowne](https://github.com/wbrowne)
+  * **Prometheus**: Fix copy paste behaving as cut and paste. [#28622](https://github.com/grafana/grafana/pull/28622), [@aocenas](https://github.com/aocenas)
+  * **StatPanel**: Fix value being under graph and reduced likelihood for white and dark value text mixing. [#28641](https://github.com/grafana/grafana/pull/28641), [@torkelo](https://github.com/torkelo)
+  * **TextPanel**: Fix problems where text panel would show old content. [#28643](https://github.com/grafana/grafana/pull/28643), [@torkelo](https://github.com/torkelo)
+
 # 7.3.0 (2020-10-28)
 
   ### Features / Enhancements