hdt: fix `gcc-13` build failure

Without the change build fails on `gcc-13` on `staging-next` as:

    src/util/StopWatch.cpp: In static member function 'static std::string StopWatch::toHuman(long long unsigned int)':
    src/util/StopWatch.cpp:166:5: error: 'uint64_t' was not declared in this scope
      166 |     uint64_t tot_secs = time/1000000;
          |     ^~~~~~~~
    src/util/StopWatch.cpp:36:1: note: 'uint64_t' is defined in header '<cstdint>'; did you forget to '#include <cstdint>'?
       35 | #include "StopWatch.hpp"
      +++ |+#include <cstdint>

0 files changed, 0 insertions, 0 deletions