docs: Add Tessell as an organisation using Argo Workflows (argoproj#1…

…0318)

Signed-off-by: Sreejith Kesavan <86766485+sreejithtessell@users.noreply.github.com>
Co-authored-by: Saravanan Balasubramanian <33908564+sarabala1979@users.noreply.github.com>

USERS.md

@@ -168,6 +168,7 @@ Currently, the following organizations are **officially** using Argo Workflows:
 1. [Styra](https://www.styra.com/)
 1. [Splunk](https://www.splunk.com/)
 1. [Sutpc](http://www.sutpc.com/)
+1. [Tessell](https://www.tessell.com/)
 1. [Threekit](https://www.threekit.com/)
 1. [Tiger Analytics](https://www.tigeranalytics.com/)
 1. [Tradeshift](https://tradeshift.com/)