Update changelog for #7940

Author: DanSheps

docs/release-notes/version-3.1.md

@@ -15,6 +15,7 @@
 * [#7812](https://github.com/netbox-community/netbox/issues/7812) - Enable change logging for image attachments
 * [#7858](https://github.com/netbox-community/netbox/issues/7858) - Standardize the representation of content types across import & export functions
 * [#7884](https://github.com/netbox-community/netbox/issues/7884) - Add FHRP groups column to interface tables
+* [#7940](https://github.com/netbox-community/netbox/issues/7940) - Add ITA multistandard outlet
 
 ### Bug Fixes