These pop up in VSCode and are pretty simple to fix:
```
nodeup/pkg/model/cloudconfig_test.go:86:17: possible nil pointer dereference (SA5011)
nodeup/pkg/model/cloudconfig_test.go:83:5: this check suggests that the pointer can be nil
nodeup/pkg/model/cloudconfig_test.go:155:17: possible nil pointer dereference (SA5011)
nodeup/pkg/model/cloudconfig_test.go:152:5: this check suggests that the pointer can be nil
nodeup/pkg/model/sysctls.go:172:12: error strings should not be capitalized (ST1005)
nodeup/pkg/model/sysctls.go:184:12: error strings should not be capitalized (ST1005)
nodeup/pkg/model/volumes.go:59:11: error strings should not be capitalized (ST1005)
```
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>