Add missing imports from typing (#933)

third_party/2and3/boto/s3/bucket.pyi

@@ -6,7 +6,7 @@ from .bucketlistresultset import BucketListResultSet
 from .connection import S3Connection
 from .key import Key
 
-from typing import Any, Dict, Optional, Text, Type
+from typing import Any, Dict, Optional, Text, Type, List
 
 class S3WebsiteEndpointTranslate:
     trans_region = ...  # type: Dict[str, str]

third_party/2and3/sqlalchemy/sql/schema.pyi

@@ -1,4 +1,4 @@
-from typing import Any, AnyStr
+from typing import Any, AnyStr, Set
 
 from .base import SchemaEventTarget, DialectKWArgs
 from .base import ColumnCollection

third_party/3/dateutil/parser.pyi

@@ -1,4 +1,4 @@
-from typing import List, Tuple, Optional, Callable, Union, IO, Any
+from typing import List, Tuple, Optional, Callable, Union, IO, Any, Dict
 from datetime import datetime
 
 __all__ = ...  # type: List[str]

third_party/3/dateutil/relativedelta.pyi

@@ -1,4 +1,4 @@
-from typing import Optional, overload, Union
+from typing import Optional, overload, Union, List
 from datetime import date, datetime, timedelta
 
 __all__ = ...  # type: List[str]

third_party/3/dateutil/tz/tz.pyi

@@ -2,7 +2,7 @@
 #
 # NOTE: This dynamically typed stub was automatically generated by stubgen.
 
-from typing import Any, Optional, Union, IO, Tuple
+from typing import Any, Optional, Union, IO, Tuple, List
 import datetime
 from ._common import tzname_in_python2 as tzname_in_python2, _tzinfo as _tzinfo
 from ._common import tzrangebase as tzrangebase, enfold as enfold