Use astropy pixel_to_pixel instead of internal calc_pixmap function

[jdavies-st]

trafficstars

Use astropy.wcs.utils.pixel_to_pixel instead of

https://github.com/spacetelescope/drizzle/blob/291b8b6249f2b24cac801ea99b383f7bf61dd1aa/drizzle/calc_pixmap.py#L5

if possible.

This will require bumping up the astropy and other dependency versions.