There's a merged pull request on the void-packages repository

[WIP] occt: update to 7.5.0.
https://github.com/void-linux/void-packages/pull/29403

Description:
ping @Piraty 

- I need to fix patches
- occt dev is now mirrored on github, I think that's a better download location
- right now, the regular git repo is down:
https://old.opencascade.com/content/scheduled-maintenance-starting-march-2-2021