add merchant hiri

_data/merchants.yml

@@ -170,6 +170,8 @@
       url: https://www.gomojomarketing.com/
     - name: Guitar Music Theory course w/ 30% XMR discount
       url: http://www.guitartheoryrevolution.info/blog/guitar-theory-revolution-store/
+    - name: Hiri - Email client
+      url: https://www.hiri.com/crypto/currency/XMR/
     - name: IdeaSoft - Full-cycle Software Development
       url: https://i-deasoft.com
     - name: Incognito Deals