Drop ioutil package.

[zhanluxianshen]

:pencil: Description

Drop ioutil package. As it is deprecation , and can be replaced well.

Deprecated: As of Go 1.16, the same functionality is now 
provided by package [io](https://pkg.go.dev/io) 
or package [os](https://pkg.go.dev/os), 
and those implementations should be preferred in new code

:link: Related Issues