New comment by sgn on void-packages repository

https://github.com/void-linux/void-packages/pull/29459#issuecomment-803544107

Comment:
Below changes will be submited separately:
- paraview: update to 5.9.0.
- vtk: devendor most of dependencies
- opencv4: update to 4.5.1. #29565 
- opencv: update to 3.4.13. #29565 
- libechonest-qt5: upstream moved
- k2pdfopt: update to 2.53. #29536