[feature request]Modify SPIFFS_OBJ_META_LEN for ESP32 and add in version

[Luc]

Hi to add time on SPIFFS :
espressif/esp-idf#1061

It need to modify SPIFFS_OBJ_META_LEN which means different mkspiffs between ESP8266 / ESP32

So I would like to suggest to add the target in version to know which SPIFFS is for which board
like for ESP32:

C:\Users\user\Desktop>mkspiffs.exe --version

mkspiffs.exe  version: 0.2.1 ESP32

and for ESP8266/8285

mkspiffs.exe  version: 0.2.1 ESP82XX

It is something possible ?

[Luc]

Thank you ^_^