ci: Add nightly builds twice a week (#88)

Signed-off-by: Christian Kadner <[email protected]>

Author: ckadner

.github/workflows/build.yml

@@ -2,6 +2,8 @@ name: Build
 
 on:
   workflow_dispatch:
+  schedule:
+    - cron: "0 8 * * 1,4" # midnight US/Pacific on Sundays and Wednesdays
   pull_request:
     branches:
       - main