ioutil has been deprecated since go 1.16, this fixes all of the
deprecated functions we are using:
ioutil.ReadFile -> os.ReadFile
ioutil.ReadAll -> io.ReadAll
ioutil.WriteFile -> os.WriteFile
ioutil.TempFile -> os.CreateTemp
ioutil.TempDir -> os.MkdirTemp
All of the above are a simple name change, the function arguments and
results are exactly the same as before.
ioutil.ReadDir -> os.ReadDir
now returns a os.DirEntry but the IsDir and Name functions work the
same. The difference is that the FileInfo must be retrieved with the
Info() function which can also return an error.
These were identified by running:
golangci-lint run --build-tags=integration ./...
We never want an empty path but always force a specific auth
file location, even if the location does not actually exist,
due to the peculiarities mentioned in the comment of the
`container.GetDefaultAuthFile` function.
