Fix syntax error in SQL query in README

Author: splasky

README.md

@@ -15,7 +15,7 @@ from sqlalchemy.engine import create_engine
 from sqlalchemy.schema import *
 engine = create_engine('datastore://test-api-1', credentials='path/to/credentials.json')
 conn = engine.connect()
-result = conn.execute("SELECT * from test_table)
+result = conn.execute("SELECT * from test_table")
 print(result.fetchall())
 ```