ci: adjust renovate to group non-majors (#12)

Reviewed-on: #12
Co-authored-by: t.behrendt <t.behrendt@t00n.de>
Co-committed-by: t.behrendt <t.behrendt@t00n.de>

renovate.json

@@ -1,3 +1,9 @@
 {
-  "$schema": "https://docs.renovatebot.com/renovate-schema.json"
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "packageRules": [
+    {
+      "matchUpdateTypes": ["patch", "minor"],
+      "groupName": "dependencies (non-major)"
+    }
+  ]
 }