New comment by reback00 on void-packages repository

https://github.com/void-linux/void-packages/pull/20615#issuecomment-609011019

Comment:
Oh! I see that it is failing xlint. I think you can try with:
```
license="custom:Proprietary"
```
just like in [opera](https://github.com/void-linux/void-packages/blob/4734690223ed77ee88e29b47f3d132c61ff34882/srcpkgs/opera/template#L9).