chore: add initial renovate config

Signed-off-by: Thomas Schuetz <thomas.schuetz@t-sc.eu>

renovate.json

@@ -0,0 +1,18 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:base",
+    "helpers:pinGitHubActionDigests"
+  ],
+  "packageRules": [
+    {
+      "matchUpdateTypes": ["minor", "patch"],
+      "matchCurrentVersion": "!/^0/",
+      "automerge": true
+    },
+    {
+      "matchManagers": ["github-actions"],
+      "automerge": true
+    }
+  ]
+}