[llvm] [Github] Add renovate configuration for Github Actions (PR #159899)

[Mend Renovate via llvm-commits]

https://github.com/renovate-bot updated https://github.com/llvm/llvm-project/pull/159899

>From cb1ddf53c73c6ec6486762ce8a01ce7fa5abf731 Mon Sep 17 00:00:00 2001
From: Mend Renovate <bot at renovateapp.com>
Date: Tue, 23 Sep 2025 15:17:31 +0000
Subject: [PATCH] Add renovate.json

---
 renovate.json | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 renovate.json

diff --git a/renovate.json b/renovate.json
new file mode 100644
index 0000000000000..5db72dd6a94fc
--- /dev/null
+++ b/renovate.json
@@ -0,0 +1,6 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended"
+  ]
+}