Add 5.20.1 release notes (#2460)
Add 5.20.1 release notes (#2460)

* Add 5.20.1 release notes

* Add remaining fixes for 5.20.1

* Update content/sensu-go/5.20/release-notes.md
sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs,sensu/sensu-docs