gcode.h: add missing <cstdint> include

[trofi]

Without the change build fails on gcc-13 as:

gcode.h:54:24: error: 'uint8_t' was not declared in this scope
   54 |                 vector<uint8_t> getBinary() const;
      |                        ^~~~~~~
gcode.h:9:1: note: 'uint8_t' is defined in header '<cstdint>'; did you forget to '#include <cstdint>'?
    8 | #include <vector>
  +++ |+#include <cstdint>
    9 |