Running gdk without any commands throws an error

Overview

In a new GDK installation using only the versions defined in .tool-versions, if you just run gdk it prints the help text, but at the end an error is also thrown.

Steps to replicate

Run gdk:

Traceback (most recent call last):
        3: from /home/axil/.asdf/installs/ruby/2.7.2/bin/gdk:23:in `<main>'
        2: from /home/axil/.asdf/installs/ruby/2.7.2/bin/gdk:23:in `load'
        1: from /home/axil/.asdf/installs/ruby/2.7.2/lib/ruby/gems/2.7.0/gems/gitlab-development-kit-0.2.12/bin/gdk:107:in `<top (required)>'
/home/axil/.asdf/installs/ruby/2.7.2/lib/ruby/gems/2.7.0/gems/gitlab-development-kit-0.2.12/bin/gdk:107:in `exit': no implicit conversion from nil to integer (TypeError)

Proposal

Since gdk should be equal to gdk help, don't throw the error.

Environment

• Operating system: Linux
• Ruby version: 2.7.2
• GDK version: lastest