Configure Renovate (#785)

* Add renovate.json

* Added a bit more configuration

also moved the config into .github subfolder so not to clutter
the root folder.

* ignore npm updates in docs

Co-authored-by: Renovate Bot <bot@renovateapp.com>
Co-authored-by: Nils Andresen <nils@nils-andresen.de>

.github/renovate.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:base"
+  ],
+  "dependencyDashboard": false,
+  "commitMessagePrefix": "chore:",
+  "labels": ["dependencies"],
+  "npm": {
+    "ignorePaths": [
+      "**/node_modules/**",
+      "**/bower_components/**",
+      "docs/**"
+    ]
+  }
+}