Add renovate

Author: inverse

.github/renovate.json

@@ -0,0 +1,9 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "rebaseWhen": "behind-base-branch",
+  "dependencyDashboard": true,
+  "labels": ["dependencies", "maintenance"],
+  "commitMessagePrefix": "⬆️",
+  "commitMessageTopic": "{{depName}}",
+  "enabledManagers": ["nvm"]
+}