Add null coalescing operator

Update UPGRADE.md

Author: pascalmoser

UPGRADE.md

@@ -1,5 +1,8 @@
 # Upgrade Notes
 
+## 2.0.1
+- [BUGFIX] Add null coalescing operator to `$options['asset_limit']` in `AssetListBuilder:getList()`
+
 ## Migrating from Version 1.x to Version 2.0.0
 
 ### Global Changes
@@ -14,4 +17,4 @@
 
 ***
 
-1.x Upgrade Notes: https://github.com/dachcom-digital/dynamic-search-data-provider-trinity/blob/1.x/UPGRADE.md
+1.x Upgrade Notes: https://github.com/dachcom-digital/dynamic-search-data-provider-trinity/blob/1.x/UPGRADE.md