sasview: fix build

pkgs/applications/science/misc/sasview/default.nix

···
     })
   ];
 
+  # AttributeError: module 'numpy' has no attribute 'float'.
+  postPatch = ''
+    substituteInPlace src/sas/sascalc/pr/p_invertor.py \
+      --replace "dtype=np.float)" "dtype=float)"
+  '';
+
   nativeBuildInputs = [
     python3.pkgs.pyqt5
     wrapQtAppsHook