chore(renovate): create PRs weekly

So the PR noise goes down a bit. Note, that security fixes are still
imediately applied[^1]

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

renovate.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
-  "extends": ["config:recommended"],
+  "extends": ["config:recommended", "schedule:earlyMondays"],
   "labels": ["dependencies"],
   "packageRules": [
     {
@@ -16,7 +16,6 @@
       "enabled": true,
       "branchTopic": "update-flake-lock",
       "commitMessageAction": "Update flake.lock",
-      "extends": ["schedule:earlyMondays"]
     }
   },
   "poetry": {