dnsdist-protocols.hh: include <cstdint>

dnsdist-protocols.hh: include <cstdint>

This fixes building dnsdist with gcc13:
```
In file included from dnsdist-protocols.cc:26:
dnsdist-protocols.hh:32:8: error: use of enum 'typeenum' without previous declaration
   32 |   enum typeenum : uint8_t
      |        ^~~~~~~~
dnsdist-protocols.hh:32:19: error: 'uint8_t' was not declared in this scope
   32 |   enum typeenum : uint8_t
      |                   ^~~~~~~
dnsdist-protocols.hh:25:1: note: 'uint8_t' is defined in header '<cstdint>'; did you forget to '#include <cstdint>'?
   24 | #include <vector>
  +++ |+#include <cstdint>
   25 | #include <string>
```