Provide support for python 3.12+

[Spikhalskiy]

When installing pypcap==-1.3.0 on python 3.12 installation fails with

      pcap.c: In function ‘__Pyx_Raise’:
      pcap.c:24328:34: error: ‘PyThreadState’ {aka ‘struct _ts’} has no member named ‘curexc_traceback’
      24328 |         PyObject* tmp_tb = tstate->curexc_traceback;
            |                                  ^~
      pcap.c:24331:19: error: ‘PyThreadState’ {aka ‘struct _ts’} has no member named ‘curexc_traceback’
      24331 |             tstate->curexc_traceback = tb;
            |                   ^~
      pcap.c: In function ‘__Pyx_PyInt_NeObjC’:
      pcap.c:24958:51: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      24958 |         const digit* digits = ((PyLongObject*)op1)->ob_digit;
            |                                                   ^~
      pcap.c: In function ‘__Pyx_PyInt_AddObjC’:
      pcap.c:26462:51: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      26462 |         const digit* digits = ((PyLongObject*)op1)->ob_digit;
            |                                                   ^~
      pcap.c: In function ‘__Pyx_PyInt_As_int’:
      pcap.c:27409:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      27409 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c:27464:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      27464 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c: In function ‘__Pyx_PyInt_As_unsigned_int’:
      pcap.c:27605:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      27605 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c:27660:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      27660 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c: In function ‘__Pyx_PyInt_As_long’:
      pcap.c:27915:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      27915 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c:27970:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      27970 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c: In function ‘__Pyx_PyInt_As_char’:
      pcap.c:28111:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      28111 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c:28166:53: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      28166 |             const digit* digits = ((PyLongObject*)x)->ob_digit;
            |                                                     ^~
      pcap.c: In function ‘__Pyx_PyIndex_AsSsize_t’:
      pcap.c:28517:45: error: ‘PyLongObject’ {aka ‘struct _longobject’} has no member named ‘ob_digit’
      28517 |     const digit* digits = ((PyLongObject*)b)->ob_digit;
            |                                             ^~
      error: command '/usr/bin/gcc' failed with exit code 1

Downgrading of python version to 3.7 solves the issue