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

opencv: update, merge with opencv4, remove python2 subpackage
https://github.com/void-linux/void-packages/pull/38628

Description:
Updated to take care of incompatibility with lapack 3.9+, and because no revdep of opencv needs opencv v3 anymore.

Neither python2 subpackage has any revdeps. Part of the ongoing python2 cleanup.

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#### Testing the changes
- I tested the changes in this PR: **YES** (builds, tested all revdeps briefly)