tech specs update

Author: mcmchris

content/hardware/07.opta/opta-family/opta/tech-specs.yml

@@ -27,7 +27,7 @@ Connectivity:
     ModBus TCP: Yes
   Bluetooth® Low Energy: Arduino Opta® WiFi Only
   Wi-Fi®: Arduino Opta® WiFi Only
-Communication interfaces:
+Communication interface:
   RS-485: Arduino Opta® RS485 & Arduino Opta® WiFi Only
   Programmable Serial ports: RS-485
 Power: