Add Renovate configuration for automated dependency updates

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Co-authored-by: voku <264695+voku@users.noreply.github.com>

Author: Copilot

.github/renovate.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended"
+  ],
+  "packageRules": [
+    {
+      "matchManagers": ["composer"],
+      "rangeStrategy": "update-lockfile"
+    }
+  ]
+}