【Go】remove ioutil pkg
@orangekame3 I don't review PRs for TF but, for what its worth, this looks good to me.  Those ioutil functions were marked as deprecated in Go 1.16; the TF bindings already require at least Go 1.18 since 527347c.  Hi @rohan100jain, Can you please review this PR ? Thank you! Hi @rohan100jain, Can you please review this PR ? Thank you! Hi @rohan100jain, Can you please review this PR ? Thank you! Hi @rohan100jain, Can you please review this PR ? Thank you! Hi @rohan100jain, Can you please review this PR ? Thank you! He doesn't seem to be active...
Hi, thank you for mantenance of TensorFlow in Go @wamuir 

I read the docs at:
https://github.com/tensorflow/tensorflow/blob/master/tensorflow/go/README.md

I also noticed that TensorFlow in Go uses some deprecated functions.
I understand that the documentation for installing the Go bindings for TensorFlow is no longer being maintained. However, I felt that using deprecated packages is also not ideal, so I've submitted a PR to fix this.

The ioutil package is already deprecated and internally calls the os package. I've rewritten the parts of the code that use ioutil to now use the os package. 

https://pkg.go.dev/io/ioutil@go1.21.1

The behavior of os.ReadDir is slightly different, but since sorting does not appear to be a requirement in this use case, I've only replaced ioutil.ReadDir with os.ReadDir.

Thanks.