_astropy_init.py uses deprecated functions

[jfoster17]

In _astropy_init.py, this package calls and uses

from astropy.config.configuration import (
        update_default_config,
        ConfigurationDefaultMissingError,
        ConfigurationDefaultMissingWarning)

But both update_default_config and ConfigurationDefaultMissingWarning are deprecated since astropy 5.0 and have been removed in the latest dev version of astropy, causing import errors for this package.

[keflavich]

@jfoster17 I don't suppose you know the easy immediate fix? I think we need to migrate the underlying package infrastructure to the more modern astropy stuff, but I don't have that process readily to mind.

[jfoster17]

I'm afraid I don't know the best way to fix/update this. I'm not really up-to-date on astropy -- but I am pinging @astrofrog since this is causes our glue test suite to fail for the latest astropy dev versions.

[astrofrog]

Looking into it now!

[astrofrog]

Fixed in #120 and pvextractor v0.4 released