Update merchants.yml

duplicate entry was deleted twice by mistake adding Web Developer - Stefanos listing again

_data/merchants.yml

@@ -76,6 +76,8 @@
       url: https://mymonero.com
     - name: Pradeep Atluri, Psychiatrist, New York
       url: http://dr.mindsci.com/
++   - name: Web Developer - Stefanos
++     url: http://www.stefanosioannou.com/web-development-monero-accepted
     - name: XMR.link OpenAlias Registry
       url: https://www.xmr.link/
     - name: XMR.to Monero to Bitcoin Payment Service