plugin prompts for mfa code but does not need it

[luchees]

We are using MFA and are assuming a role for using AWS cli.

Our MFA code gets cached by serverless and by AWS cli.
However when we start using the latest-layer-version plugin and run serverless package we get a prompt asking for the mfa code.
We do not need to fill it and the serverless package command executes successfully.

I'm using your plugin version: 2.1.1
serverless version : 2.34.0

This is not really a blocking issue but I think this is something that can be improved.