Update setup.py to build against python 3.11

[perestoronin]

Please accept PR to fix build xmlstarlet cffi with new python version

pip install xmlstarlet
Collecting xmlstarlet
  Downloading xmlstarlet-1.6.8.tar.gz (715 kB)
     ---------------------------------------- 715.3/715.3 kB 8.9 MB/s eta 0:00:00
  Installing build dependencies ... done
  Getting requirements to build wheel ... done
  Installing backend dependencies ... done
  Preparing metadata (pyproject.toml) ... error
  error: subprocess-exited-with-error

  × Preparing metadata (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [1 lines of output]
      error in xmlstarlet setup command: 'python_requires' must be
           a string containing valid version specifiers; Invalid specifier: '>=3.6.*'
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.

note: This is an issue with the package mentioned above, not pip.
hint: See above for details.