Release 2.5.0-beta1 (#5470)

* Update platform.txt version to 2.5.0-beta1

Author: devyte

platform.txt

@@ -5,8 +5,8 @@
 # For more info:
 # https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5---3rd-party-Hardware-specification
 
-name=ESP8266 Boards (2.5.0-dev)
-version=2.5.0-dev
+name=ESP8266 Boards (2.5.0-beta1)
+version=2.5.0-beta1
 
 runtime.tools.xtensa-lx106-elf-gcc.path={runtime.platform.path}/tools/xtensa-lx106-elf
 runtime.tools.esptool.path={runtime.platform.path}/tools/esptool