Update diagram of the Rust Board with version 1.2

[SergioGasquez]

With #103, https://github.com/ferrous-systems/espressif-trainings/blob/main/book/src/assets/rust_board_v1_diagram.svg was added, this diagram shows v1 of the board. Would it be possible to use v1.2 https://github.com/esp-rs/esp-rust-board/blob/master/assets/rust_board_v1.2_diagram.png