Fix Renovate schedule (#329)

This schedule is not how often Renovate should run, but rather the time
window in which Renovate is allowed to create branches. [Docs recommend
setting a larger time window, depending on when the used instance is set
to run][1]. Increase the window, as it's not documented how often
Renovate for GitHub (Mend-hosted instance) runs.

[1]: https://docs.renovatebot.com/configuration-options/#schedule

.github/renovate.json5

@@ -5,7 +5,7 @@
   ],
   "schedule": [
     // Runs once, despite '*' minutes (https://docs.renovatebot.com/configuration-options/#schedule)
-    "* 6 * * 1",
+    "* 0-6 * * 1",
   ],
   "ignorePaths": [
     "**/test_resources/**",