CI: take advantage of zig build concurrency

I ain't afraid of no ghost.

This reverts commit 14a176b9b16e07a66a2f9cd485aaf80fed0f5a12.
8d4067e7a3Andrew Kelley committed on 3/15/2023, 5:48:14 PMparent030742f
7 files changedLine totals unavailable