Auto-assign @luka to renovate MRs

renovate.json

@@ -2,5 +2,8 @@
     "$schema": "https://docs.renovatebot.com/renovate-schema.json",
     "extends": [
         "local>stackspin/renovate-config:default"
+    ],
+    "assignees": [
+        "luka"
     ]
 }