drop io/utils package.

[zhanluxianshen]

/kind cleanup

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

[CLAassistant]

All committers have signed the CLA.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.73%. Comparing base (1c5f633) to head (dbc12df).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1188   +/-   ##
=======================================
  Coverage   98.73%   98.73%           
=======================================
  Files          31       31           
  Lines        2851     2851           
=======================================
  Hits         2815     2815           
  Misses         29       29           
  Partials        7        7           

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[zhanluxianshen]

thanks