[gh actions][xs]: run the job every 6 hours.

The reason is that the upstream repo is not fully updated on regular basis. At 23:59 GMT it adds a new data file per date but the files we're depending on are updated manually after that.

.github/workflows/actions.yml

@@ -1,6 +1,6 @@
 on:
-  push:
-    branches: [ master ]
+  schedule:
+    - cron:  '0 */6 * * *'
 
 jobs:
   build: