build: update cron in workflow

This commit arbitrarily modifies the cron value in the workflow yml to
update where notifications are sent.

From the documentation: "If a different user updates the cron syntax in
the workflow file, subsequent notifications will be sent to that user
instead.".

.github/workflows/main.yml

@@ -8,7 +8,7 @@ on:
   pull_request:
     branches: ["backtrace"]
   schedule:
-    - cron: "0 0 * * *"
+    - cron: '0 0 * * *'
 
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch: