New review comment by marmeladema on void-packages repository

https://github.com/void-linux/void-packages/pull/40515#discussion_r1021269216

Comment:
According to @ericonr in https://github.com/void-linux/void-packages/pull/26888#discussion_r723785148

> If you use date inside some of the pre_ functions then it uses SOURCE_DATE_EPOCH automatically.

We agreed at the time that it was fine to use `date -u` here. Additionally, I prefer having the correct build date when building locally.