DEVX-299 - feat: adopt leanix renovate preset

**WHY**
This configures renovate to automatilly pin all dependencies as suggested to do by InfoSec in context of the latest npm supply chain attack.
The preset applies dependency management best practices to the repository.
Additionally it enables us to adjust renovate's core config consistently and much faster in the future.

**WHAT**
Adopt the [LeanIX renovate preset](https://github.com/leanix/.github/blob/main/default.json).

**WHAT TO EXPECT?**
Once this change has been merged renovate will monitor the repository's dependencies.
It will create a change request pinning dependencies to fixed versions.

The preset aims to control central configuration parameters. You might extend the configuration
to custimze the behavior. Customizations that would be generally beneficial may be proposed for
adoption in the [preset](https://github.com/leanix/.github/blob/main/default.json) itself.

Author: r0binary-sap

.github/renovate.json

@@ -1,15 +1,24 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
-  "extends": ["config:recommended"],
+  "extends": [
+    "github>leanix/.github"
+  ],
   "automerge": false,
   "prConcurrentLimit": 1,
   "packageRules": [
     {
-      "matchPackagePatterns": ["*"],
-      "matchUpdateTypes": ["patch", "minor"],
+      "matchPackagePatterns": [
+        "*"
+      ],
+      "matchUpdateTypes": [
+        "patch",
+        "minor"
+      ],
       "groupName": "all dependencies"
     }
   ],
-  "schedule": ["* 0-3 * * *"],
+  "schedule": [
+    "* 0-3 * * *"
+  ],
   "timezone": "Europe/Berlin"
 }