CI: add_version: move off the start of the hour

Due to load peak at 0 minutes, it may fail to get a runner.
Github tries to allocate a runner for ~15 minutes.

.github/workflows/add_version.yml

@@ -4,7 +4,7 @@ on:
   workflow_dispatch: {}
   schedule:
     # Every N hours
-    - cron: '0 */4 * * *'
+    - cron: '25 */4 * * *'
 
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   contents: write