ci: add renovate actions updates

Author: altaywtf

.github/renovate.json

@@ -0,0 +1,29 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:recommended",
+    "helpers:pinGitHubActionDigests"
+  ],
+  "enabledManagers": ["github-actions"],
+  "timezone": "Europe/Istanbul",
+  "schedule": ["before 6am on Monday"],
+  "semanticCommits": "enabled",
+  "semanticCommitType": "ci",
+  "labels": ["dependencies", "github-actions"],
+  "packageRules": [
+    {
+      "description": "Group non-major GitHub Actions updates.",
+      "matchManagers": ["github-actions"],
+      "matchUpdateTypes": ["minor", "patch", "digest", "pin"],
+      "groupName": "GitHub Actions patch/minor",
+      "groupSlug": "github-actions"
+    },
+    {
+      "description": "Keep major GitHub Actions updates separate from lower-risk bumps.",
+      "matchManagers": ["github-actions"],
+      "matchUpdateTypes": ["major"],
+      "groupName": "GitHub Actions major",
+      "groupSlug": "github-actions-major"
+    }
+  ]
+}