Install automatically when using .binary_version

[alexppg]

When using .kubectl_version or .helm_version, the manager should install the binary version when detecting that's not installed.

[gcavalcante8808]

@alexppg at least for helm, I use the following script to add this behavior:

#! /usr/bin/env bash

if [[ -f ".helm_version" ]]; then
    helmenv install "$(cat .helm_version)"
    helmenv use "$(cat .helm_version)"
fi

exec helm-wrapper "$@"

Just install the script above as /usr/local/bin/helm and left helm-wrapper and helmenv in the path.