[github] Only publish releases on weekdays

Generally nothing happens in the Dawn repository on weekends, so don't
bother wasting resources rebuilding everything on Sat/Sun night.

No-Try: true
Bug: 493681577
Change-Id: If3304a736e74ce974d28356923c8726fc972c4ee
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/297895
Commit-Queue: Brandon Jones <bajones@chromium.org>
Auto-Submit: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>

.github/workflows/release.yml

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 3ec43e9..69b9ec6 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -3,7 +3,7 @@
 on:
   workflow_dispatch: {}
   schedule:
-    - cron: '50 5 * * *'  # 05:50 UTC (21:50 PST, 22:50 PDT)
+    - cron: '50 5 * * 2-6'  # 05:50 UTC, Tue-Sat morning (21:50 PST / 22:50 PDT Mon-Fri night)
 
 permissions:
   contents: write