update the date

Signed-off-by: Christopher Guindon <chris.guindon@eclipse-foundation.org>

content/events/2020-04-09-iotandedgeday2020.md

 +++
-date = "2020-03-09"
+date = "2020-03-19"
 event_date = "April 9, 2020"
 link = "https://iot.eclipse.org/eclipse-iot-and-edge-day-san-jose-2020/"
 location = "San Jose, California, USA"