Update ESP8266 FQBN in .travis.yml

Some of the menu IDs for the ESP8266 boards were recently changed, which caused compilation in the Travis CI build to fail with "Invalid option for board" errors.

Author: per1234

.travis.yml

@@ -3,8 +3,8 @@ env:
   global:
     - IDE_VERSION=1.8.7
   matrix:
-    - EXAMPLE="AdafruitHuzzahESP8266" BOARD="esp8266:esp8266:huzzah:FlashSize=4M3M,CpuFrequency=80"
-    - EXAMPLE="AdafruitHuzzahESP8266Secure" BOARD="esp8266:esp8266:huzzah:FlashSize=4M3M,CpuFrequency=80"
+    - EXAMPLE="AdafruitHuzzahESP8266" BOARD="esp8266:esp8266:huzzah:eesz=4M3M,xtal=80"
+    - EXAMPLE="AdafruitHuzzahESP8266Secure" BOARD="esp8266:esp8266:huzzah:eesz=4M3M,xtal=80"
     - EXAMPLE="ArduinoEthernetShield" BOARD="arduino:avr:uno"
     - EXAMPLE="ArduinoMKRGSM1400" BOARD="arduino:samd:mkrgsm1400"
     - EXAMPLE="ArduinoMKRGSM1400Secure" BOARD="arduino:samd:mkrgsm1400"