Reduce CI load from renovate

Author: alexeagle

renovate.json

@@ -9,11 +9,17 @@
     "replacements:all",
     "workarounds:all"
   ],
+  "schedule": ["before 4am on monday"],
   "packageRules": [
     {
       "matchFiles": ["MODULE.bazel"],
       "matchPackageNames": ["pre-commit/mirrors-prettier"],
       "enabled": false
+    },
+    {
+      "matchManagers": ["gomod"],
+      "groupName": "all Go dependencies",
+      "groupSlug": "all-go-deps"
     }
   ],
   "labels": ["deps"]