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**Description**

A sql sensor which uses Standard SQL due to default one uses legacy sql


**Use case / motivation**

Currently (correct me if I am wrong!), the sql sensor only supports legacy sql. If I want to poke a BQ table, I do not think I can do that using standard sql right now.


**Are you willing to submit a PR?**

If community approves of this idea, sure!


tests/sensors/test_sql_sensor.py
#
#
#
import os
import unittest
from unittest import mock
import pytest
from airflow.exceptions import AirflowException
from airflow.models.dag import DAG
from airflow.sensors.sql import SqlSensor
from airflow.utils.timezone import datetime
from tests.providers.apache.hive import TestHiveEnvironment
DEFAULT_DATE = datetime(2015, 1, 1)
TEST_DAG_ID = 'unit_test_sql_dag'
class TestSqlSensor(TestHiveEnvironment):
    def setUp(self):
        super().setUp()
        args = {'owner': 'airflow', 'start_date': DEFAULT_DATE}
        self.dag = DAG(TEST_DAG_ID, default_args=args)
    def test_unsupported_conn_type(self):