Update aws-iot example with new configuration // Resolve #242

Author: valeros

examples/espidf-aws-iot/platformio.ini

@@ -13,6 +13,10 @@ framework = espidf
 board = esp32dev
 monitor_speed = 115200
 build_flags =
-  -DCOMPONENT_EMBED_TXTFILES=src/private.pem.key:src/certificate.pem.crt:src/aws-root-ca.pem
   -DCONFIG_WIFI_SSID=\"ESP_AP\"
   -DCONFIG_WIFI_PASSWORD=\"MYPASS\"
+
+board_build.embed_txtfiles = 
+  src/private.pem.key
+  src/certificate.pem.crt
+  src/aws-root-ca.pem