Sipeed Longan Nano v1.1- RISC-V GD32VF103CBT6 Development Board

As an updated version to Sipeed Longan Nano, the Sipeed Longan Nano V1.1 development board has been modified the pin definitions of headers and board outline by us. Also, for looking tidy, we gifted it a new shell. The board is based on GD32VF103CBT6 MCU with the RISC-V 32-bit core of GigaDevice.