docs: add hurb to readme (#745)

Summary of Changes
Add [Hurb](https://hurb.com) as a user of Amundsen

Documentation
Changed the [README.md](https://github.com/lyft/amundsen/blob/master/README.md)

CheckList
Make sure you have checked all steps below to ensure a timely review.

[] PR title addresses the issue accurately and concisely, including a title prefix.
[] PR includes a summary of changes.
[] My commits follow the guidelines from "How to write a good git commit message"

README.md

@@ -217,6 +217,7 @@ Currently **officially** using Amundsen:
 1. [Edmunds](https://www.edmunds.com/)
 1. [Everfi](https://everfi.com/)
 1. [Gusto](https://gusto.com/)
+1. [Hurb](https://hurb.com)
 1. [ING](https://www.ing.com/Home.htm)
 1. [iRobot](https://www.irobot.com)
 1. [LMC](https://www.lmc.eu/cs/)