docs: add Andgo Systems to users list (#18157)

Signed-off-by: Erik Frederiksen <rik.the.vik@gmail.com>

USERS.md

@@ -22,6 +22,7 @@ Currently, the following organizations are **officially** using Argo CD:
 1. [Amadeus IT Group](https://amadeus.com/)
 1. [Ambassador Labs](https://www.getambassador.io/)
 1. [Ancestry](https://www.ancestry.com/)
+1. [Andgo Systems](https://www.andgosystems.com/)
 1. [ANSTO - Australian Synchrotron](https://www.synchrotron.org.au/)
 1. [Ant Group](https://www.antgroup.com/)
 1. [AppDirect](https://www.appdirect.com)