Docs: concurrent writes permission missing

There was a missing permission in the list of DynamoDB list of permissions for concurrent writes.

docs/usage/writing/writing-to-s3-with-locking-provider.md

@@ -95,6 +95,7 @@ In DynamoDB, you need those permissions:
 - dynamodb:Query
 - dynamodb:PutItem
 - dynamodb:UpdateItem
+- dynamodb:DeleteItem
 
 ### Enabling concurrent writes for alternative clients