Failure to install packages in python 3.8 and 3.9

It looks like something to do with lxml

here is one of the failed builds for python 3.8:

The error message ocurres when installing mt_metadata:

Collecting lxml (from obspy->mt-metadata==0.3.3)
  Downloading lxml-5.0.0.tar.gz (3.8 MB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 3.8/3.8 MB 121.6 MB/s eta 0:00:00
  Preparing metadata (setup.py): started
  Preparing metadata (setup.py): finished with status 'error'
  error: subprocess-exited-with-error

  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [5 lines of output]
      /tmp/pip-install-xmiovcn1/lxml_1e9ca0373c8e497388ddc934d295d87c/setup.py:67: DeprecationWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html
        import pkg_resources
      Building lxml version 5.0.0.
      Building without Cython.
      Error: Please make sure the libxml2 and libxslt development packages are installed.
      [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.
Error: Process completed with exit code 1.

Maybe start by checking if mt_metadata alone is suffering this issue?

simpeg / aurora

Failure to install packages in python 3.8 and 3.9 #313