fix typo

Author: alrocar

alter_default_value_in_column/datasources/analytics_events.datasource

@@ -8,7 +8,7 @@ SCHEMA >
     `session_id` String `json:$.session_id` DEFAULT '',
     `action` LowCardinality(String) `json:$.action` DEFAULT 'None',
     `version` LowCardinality(String) `json:$.version` DEFAULT '1.0',
-    `payload` String `json:$.payload` DEFAULT '{}',
+    `payload` String `json:$.payload` DEFAULT '{}'
 
 ENGINE "MergeTree"
 ENGINE_PARTITION_KEY "toYYYYMM(timestamp)"