License Management fails on some Ruby projects that have license_finder included in the Gemfile

Summary

Running the license management image on GitLab EE fails with a complaint that it can't find a specific version of license_finder

Steps to reproduce

• Install the GitLab EE GDK
• Run the license management image on it.
• It fails with a complaint that it can't find a specific version of license_finder.

Example Project

https://gitlab.com/gitlab-org/gitlab-ee/

What is the current bug behavior?

The License Management image fails and doesn't return data about the licenses present the project and it's dependencies.

What is the expected correct behavior?

The License Management image runs succesfully and returns data about the licenses present the project and it's dependencies.

Relevant logs and/or screenshots

$ cd gdk-ee/gitlab
$ docker run --volume "$PWD":/code --rm registry.gitlab.com/gitlab-org/security-products/license-management:latest /run.sh /code
...
Successfully installed multi_xml-0.6.0
When you HTTParty, you must party hard!
Successfully installed httparty-0.16.2
Successfully installed rubyzip-1.2.1
Successfully installed thor-0.20.0
Successfully installed parslet-1.8.2
Successfully installed toml-0.2.0
Successfully installed with_env-1.1.0
Successfully installed xml-simple-1.1.5
Successfully installed license_finder-5.2.3
Parsing documentation for multi_xml-0.6.0
Installing ri documentation for multi_xml-0.6.0
Parsing documentation for httparty-0.16.2
Installing ri documentation for httparty-0.16.2
Parsing documentation for rubyzip-1.2.1
Installing ri documentation for rubyzip-1.2.1
Parsing documentation for thor-0.20.0
Installing ri documentation for thor-0.20.0
Parsing documentation for parslet-1.8.2
Installing ri documentation for parslet-1.8.2
Parsing documentation for toml-0.2.0
Installing ri documentation for toml-0.2.0
Parsing documentation for with_env-1.1.0
Installing ri documentation for with_env-1.1.0
Parsing documentation for xml-simple-1.1.5
Installing ri documentation for xml-simple-1.1.5
Parsing documentation for license_finder-5.2.3
Installing ri documentation for license_finder-5.2.3
Done installing documentation for multi_xml, httparty, rubyzip, thor, parslet, toml, with_env, xml-simple, license_finder after 2 seconds
9 gems installed
Could not find proper version of license_finder (3.1.1) in any of the sources
Run `bundle install` to install missing gems.

Results of GitLab environment info

Results of GitLab application Check

This is irrelevant to GitLab's environment, this is an issue with the License Management image (see https://gitlab.com/gitlab-org/security-products/license-management).