Use numpy.linspace in ipol.interpolate_polar (#576)
Use numpy.linspace in ipol.interpolate_polar (#576)

Co-authored-by: Kai Mühlbauer <06809f38505a7ac2c0f511e47d8d15c86fc98e7c@wradlib.org>
kmuehlbauer/wradlib,wradlib/wradlib,heistermann/wradlib,wradlib/wradlib,kmuehlbauer/wradlib,heistermann/wradlib