Include cstdint in gz

[adamant-pwn]

On some setups, I get a bunch of errors that look like

In file included from /home/adamant/sshash-jermp/include/gz/zip_stream.cpp:1:
/home/adamant/sshash-jermp/include/gz/zip_stream.hpp:121:5: error: ‘uint32_t’ does not name a type
  121 |     uint32_t get_crc() const;
      |     ^~~~~~~~
/home/adamant/sshash-jermp/include/gz/zip_stream.hpp:67:1: note: ‘uint32_t’ is defined in header ‘<cstdint>’; did you forget to ‘#include <cstdint>’?
   66 | #include <vector>
  +++ |+#include <cstdint>
   67 | 
/home/adamant/sshash-jermp/include/gz/zip_stream.hpp:124:5: error: ‘uint32_t’ does not name a type
  124 |     uint32_t get_in_size() const;
      |     ^~~~~~~~
/home/adamant/sshash-jermp/include/gz/zip_stream.hpp:124:5: note: ‘uint32_t’ is defined in header ‘<cstdint>’; did you forget to ‘#include <cstdint>’?
/home/adamant/sshash-jermp/include/gz/zip_stream.hpp:137:5: error: ‘uint32_t’ does not name a type
  137 |     uint32_t crc_;
      |     ^~~~~~~~
/home/adamant/sshash-jermp/include/gz/zip_stream.hpp:137:5: note: ‘uint32_t’ is defined in header ‘<cstdint>’; did you forget to ‘#include <cstdint>’?
/home/adamant/sshash-jermp/include/gz/zip_stream.hpp:180:5: error: ‘uint32_t’ does not name a type
  180 |     uint32_t get_crc() const;
      |     ^~~~~~~~

This include fixes it.

[jermp]

Thanks!