[Enhancement] Support type hints and dataclass compatibility for Python under 3.10 (#63131)

Why I'm doing:
starrocks-python-client support most of the python3 version, but there are some new features that is not compatibility for Python under 3.10

What I'm doing:
use Union for supporting type hints in python under 3.10
not setting kw_only for dataclasses in python under 3.10

contrib/starrocks-python-client/starrocks/dialect.py

@@ -15,6 +15,7 @@
 import re
 from textwrap import dedent
 import time
+from typing import Union
 
 from sqlalchemy import Connection, exc, schema as sa_schema
 from sqlalchemy.dialects.mysql.pymysql import MySQLDialect_pymysql
@@ -423,7 +424,7 @@ class StarRocksDialect(MySQLDialect_pymysql):
         return _reflection.StarRocksTableDefinitionParser(self, preparer)
 
     def _read_from_information_schema(
-        self, connection: Connection, inf_sch_table: str, charset: str | None = None, **kwargs
+        self, connection: Connection, inf_sch_table: str, charset: Union[str, None] = None, **kwargs
     ):
         def escape_single_quote(s):
             return s.replace("'", "\\'")
@@ -449,7 +450,7 @@ class StarRocksDialect(MySQLDialect_pymysql):
         return rows
     
     @reflection.cache
-    def _setup_parser(self, connection: Connection, table_name: str, schema: str | None = None, **kw):
+    def _setup_parser(self, connection: Connection, table_name: str, schema: Union[str, None] = None, **kw):
         charset = self._connection_charset
         parser = self._tabledef_parser
 

contrib/starrocks-python-client/starrocks/reflection.py

@@ -16,7 +16,7 @@
 import dataclasses
 import json
 import re
-from typing import Any
+from typing import Any, Union
 
 from sqlalchemy.dialects.mysql.types import DATETIME
 from sqlalchemy.dialects.mysql.types import TIME
@@ -27,12 +27,13 @@ from sqlalchemy import log
 from sqlalchemy import types as sqltypes
 from sqlalchemy import util
 
-
-@dataclasses.dataclass(kw_only=True)
+# kw_only is added in python 3.10
+# https://docs.python.org/3/library/dataclasses.html#dataclasses.dataclass
+@dataclasses.dataclass(**dict(kw_only=True) if 'KW_ONLY' in dataclasses.__all__ else {})
 class ReflectedState(object):
     """Stores informations about table or view."""
 
-    table_name: str | None = None
+    table_name: Union[str, None] = None
     columns: list[dict] = dataclasses.field(default_factory=list)
     table_options: dict[str, str] = dataclasses.field(default_factory=dict)
     keys: list[dict] = dataclasses.field(default_factory=list)