Update README.md with build instructions instead of referencing the ferret.pmel.noaa.gov site that is currently unavailable
Update README.md with build instructions instead of referencing the ferret.pmel.noaa.gov site that is currently unavailable

NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret,NOAA-PMEL/PyFerret