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

rtl8812au-dkms: update to 20210629.
https://github.com/void-linux/void-packages/pull/39536

Description:
Old upstream stated their version was now obselete, and directed to this new upstream.

The old version also relied on headers that do not exist in 5.15+

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#### Testing the changes
- I tested the changes in this PR: **briefly** (dkms module builds, don't have the hardware)

@tsjk can you test this?