refactor: move from io/ioutil to io and os packages

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

cmd/linux.go

@@ -2,7 +2,6 @@ package cmd
 
 import (
 	"fmt"
-	"io/ioutil"
 	"net/url"
 	"os"
 	"runtime"
@@ -95,7 +94,7 @@ func GetLinuxDistroInfo() *DistroInfo {
 	}
 	_, err := os.Stat("/etc/os-release")
 	if !os.IsNotExist(err) {
-		osRelease, _ := ioutil.ReadFile("/etc/os-release")
+		osRelease, _ := os.ReadFile("/etc/os-release")
 		result = parseOsRelease(string(osRelease))
 	}
 	return result