undefined: io.Discard and io.ReadAll in latest code push

[DrewCurd]

Describe the bug
Currently, the Go Client is broken due to io.Discard and io.ReadAll being undefined in latest version of the code.

Expected behavior
Should be able to run the Go Client without getting undefined errors unrelated to my code.

Logs

# go.mongodb.org/atlas/mongodbatlas
/root/go/src/go.mongodb.org/atlas/mongodbatlas/mongodbatlas.go:450:20: undefined: io.Discard
/root/go/src/go.mongodb.org/atlas/mongodbatlas/mongodbatlas.go:521:15: undefined: io.ReadAll
Error: Process completed with exit code 2.

[gssbzn]

Hi @DrewCurd, I'm assuming this is a go version prior to 1.16 where io.Discard and io.ReadAll where added and ioutil deprecated, sadly we dropped support for any version prior to 1.16 (#242) in line with our support policy, from our README

Note that go-client-mongodb-atlas only supports the two most recent major versions of Go.

Which is also aligned with the go support policy

https://golang.org/doc/devel/release#policy