Cast SQLServer's :datetimeoffset to time

[vividmuimui]

This PR is a PR to support the datetimeoffset type in SQLServer.

irb(main):009> Product.columns_hash["CreatedAt"].type
=> :datetimeoffset

irb(main):010> Product.columns_hash["CreatedAt"]
=>
#<ActiveRecord::ConnectionAdapters::SQLServer::Column:0x0000000122cfeb08
 @collation=nil,
 @comment=nil,
 @default=nil,
 @default_function=nil,
 @is_identity=false,
 @is_primary=false,
 @name="CreatedAt",
 @null=false,
 @ordinal_position=2,
 @sql_type_metadata=#<ActiveRecord::ConnectionAdapters::SqlTypeMetadata:0x0000000122bb5698 @limit=nil, @precision=7, @scale=nil, @sql_type="datetimeoffset(7)", @type=:datetimeoffset>,
 @table_name="Products">

[scarroll32]

@vividmuimui could you please add a comment to indicate datetimeoffset is SQLServer only.