Fixed Travis STM32 board

.travis.yml

@@ -5,7 +5,7 @@ env:
     # see https://github.com/arduino/Arduino/blob/master/build/shared/manpage.adoc#options
     # and https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5-3rd-party-Hardware-specification#boardstxt
     - BOARD="esp32:esp32:esp32"
-    - BOARD="STM32:stm32:GenF1:pnum=NUCLEO_L452REP"
+    - BOARD="STM32:stm32:Nucleo_64:pnum=NUCLEO_L452REP"
     - BOARD="esp8266:esp8266:generic:xtal=80,ResetMethod=ck,CrystalFreq=26,FlashFreq=40,FlashMode=qio,eesz=512K"
     - BOARD="arduino:samd:arduino_zero_native"
     - BOARD="arduino:sam:arduino_due_x"