The io/ioutil package has been deprecated in Go 1.16. 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>
(cherry picked from commit c55a4ac779)
Signed-off-by: Cory Snider <csnider@mirantis.com>