Delay nightly wheel builds by 2 hours

Pandas builds at 3:27 and we build at 3:47, but their wheels take nearly
2 hours to build, so delay ours to avoid missing wheels.

Fixes matplotlib#24815

Author: QuLogic

.github/workflows/tests.yml

@@ -13,8 +13,8 @@ on:
     branches-ignore:
       - v[0-9]+.[0-9]+.[0-9x]+-doc
   schedule:
-    # 3:47 UTC on Saturdays
-    - cron: "47 3 * * 6"
+    # 5:47 UTC on Saturdays
+    - cron: "47 5 * * 6"
   workflow_dispatch:
     workflow: "*"