Remove schedule config for lockFileMaintenance (#149)

Why these changes are being introduced:
* Renovate did not create a PR with updates to the lock
file, and it may be due to the conflicting schedule
settings by extending the 'schedule:nonOfficeHours' preset
while also setting 'lockFileMaintenance.schedule' (see
job https://developer.mend.io/github/MITLibraries/alma-sapinvoices-ui/-/job/019a3281-259c-7e55-ab8b-4772d7b4f5ee).
This change aims to resolve scheduling conflicts.

How this addresses that need:
* Update renovate.json

Side effects of this change:
* None

Relevant ticket(s):
* None

Author: jonavellecuerdo

renovate.json

@@ -9,10 +9,7 @@
     "pipenv"
   ],
   "lockFileMaintenance": {
-    "enabled": true,
-    "schedule": [
-      "* 0-4 * * 1"
-    ]
+    "enabled": true
   },
   "timezone": "America/New_York",
   "vulnerabilityAlerts": {