coot: remove raster3d temporarily (#2180)

Author: YoshitakaMo

Formula/coot.rb

@@ -28,7 +28,6 @@ class Coot < Formula
   depends_on "brewsci/bio/gemmi"
   depends_on "brewsci/bio/libccp4"
   depends_on "brewsci/bio/mmdb2"
-  depends_on "brewsci/bio/raster3d"
   depends_on "brewsci/bio/ssm"
   depends_on "cairo"
   depends_on "coordgen"