Fix typo in example 4 (#9)

Author: dawidwys

flink_table_api_python/examples/table/example_04_creating_tables.py

@@ -77,4 +77,4 @@ def run():
         'kafka.retention.time' = '0 ms',
         'key.format' = 'json-registry',
         'value.format' = 'json-registry'
-      )""" % TARGET_TABLE1)
+      )""" % TARGET_TABLE2)