CubeCell – Dev-Board (V2) (cubecell_board_v2) build fails with new ST7735

[StandBackBurrito]

@Heltec-Aaron-Lee I noticed you recently Added st7735 support. I a m trying it out on a CubeCell – Dev-Board (V2) and running into the following issues

HT_st7735.h defines the DC pin as GPIO8

#define ST7735_DC_Pin        GPIO8

The CubeCell-Dev-Board does not have a GPIO8 on V1 or V2. This is causing the build to fail until the define is changed in the header.

https://github.com/HelTecAutomation/CubeCell-Arduino/blob/16549f2000362873ca0eb9788101054defb92f4c/libraries/DISPLAY/src/HT_st7735.h#LL21C1-L21C35