fix compilation of hp64k.cc due to undeclared uint16_t

[kopp]

I get compilation of srecord failing because uint16_t is unknown (see logs ):

[  3%] Building CXX object srecord/CMakeFiles/lib_srecord.dir/arglex/tool/input.cc.o
In file included from /home/builder/.cache/aurutils/sync/srecord/src/srecord-1.65.0-Source/srecord/arglex/tool/input.cc:38:
/home/builder/.cache/aurutils/sync/srecord/src/srecord-1.65.0-Source/./srecord/input/file/hp64k.h:82:21: error: ‘uint16_t’ has not been declared
   82 |     bool read_u16be(uint16_t *dest);
      |                     ^~~~~~~~
/home/builder/.cache/aurutils/sync/srecord/src/srecord-1.65.0-Source/./srecord/input/file/hp64k.h:1:1: note: ‘uint16_t’ is defined in header ‘<cstdint>’; this is probably fixable by adding ‘#include <cstdint>’
  +++ |+#include <cstdint>
    1 | //
make[2]: *** [srecord/CMakeFiles/lib_srecord.dir/build.make:219: srecord/CMakeFiles/lib_srecord.dir/arglex/tool/input.cc.o] Error 1

Does anything speak against this change?