fix build failure with gcc-13

[emollier]

Attempting to build ivar up to version 1.4.1 with Gcc 13 will result with the following errors:

primer_bed.h:13:3: error: ‘uint32_t’ does not name a type
   13 |   uint32_t start;  // 0 based
      |   ^~~~~~~~
primer_bed.h:6:1: note: ‘uint32_t’ is defined in header ‘<cstdint>’; did you forget to ‘#include <cstdint>’?
    5 | #include <vector>
  +++ |+#include <cstdint>
    6 |
[…]
parse_gff.h:47:3: error: ‘uint64_t’ does not name a type
   47 |   uint64_t get_start();
      |   ^~~~~~~~
parse_gff.h:6:1: note: ‘uint64_t’ is defined in header ‘<cstdint>’; did you forget to ‘#include <cstdint>’?
    5 | #include <regex>
  +++ |+#include <cstdint>
    6 | #include <sstream>

Per the hints, this patch will resolve the build problem with the newer compiler version. This problem has been initially reported in Debian Bug#1037700.

[emollier]

Hm, I seem to have mistyped the version number. I was of course referring to ivar up to version 1.4.2. :)