docs: Add information for release selection

docs/mkdocs.yml

@@ -13,6 +13,15 @@ theme:
   favicon: 'assets/images/favicon.ico'
   feature:
     tabs: true
+    releases:
+      - name: 'Rocko'
+        path: 'yocto-customer/build-exceet-rocko'
+        current: true
+        latest: true
+      - name: 'Morty'
+        path: 'yocto-customer/build-exceet-morty'
+        current: false
+        latest: false
   custom_dir: 'mkdocs-material-kontron/material'
 
 site_url: https://docs.kontron-electronics.de/