fix: Attempt at grouping lockfile maintenance (#2918)

Not sure if this will work, but it will be quite nice if all the
lockfile maintenance can be done in 1 PR to reduce weekly chore.

Author: another-rex

renovate.json

@@ -12,7 +12,8 @@
   "osvVulnerabilityAlerts": true,
   "lockFileMaintenance": {
     "enabled": true,
-    "schedule": ["before 6am on wednesday"]
+    "schedule": ["before 6am on wednesday"],
+    "groupName": "lockfile maintenance"
   },
   "git-submodules": {
     "enabled": false