does flake updates every day at noon

Since we have Hydra set up now for the flake update branch, this will
let us see if we can upgrade safely, as well as pushing more artifacts
into the cache.

Signed-off-by: ahuston-0 <aliceghuston@gmail.com>

.github/workflows/flake-update.yml

@@ -3,7 +3,7 @@ on:
   repository_dispatch:
   workflow_dispatch:
   schedule:
-    - cron: "51 2 * * 1,4"
+    - cron: "00 12 * * *"
 jobs:
   createPullRequest:
     runs-on: ubuntu-latest