modulesync 2.2.0 and allow puppet 6.x

fix syntax of config_mode fact example

modulesync 2.3.1

modulesync 2.4.0

Note this silently adds RHEL 8 support. Because it's not tested I
haven't added it to metadata.json, but the package name matches Fedora.

This module doesn't work on anything but Red Hat based systems so we can
drop the Arch and EC 2 nodesets.

The tests also depend on the order so this sets the state prior to
running a class.

Docker doesn't support selinux so the beaker-vagrant gem is added.

When the builder is loaded from the default builder, we need to make
sure we include the right packages.

By only including the build directories when building modules, we
maintain a cleaner system.

Builder improvements and acceptance tests

modulesync 2.5.1 and drop Puppet 4

stdlib 6.0.0 is due to be released soon.
This module has already dropped support for puppet 4 and/or doesn't
use the updated stdlib `merge` function.

See
https://github.com/puppetlabs/puppetlabs-stdlib/blob/217068f97edd2396ce37ac8c1bd7e23da621d6be/CHANGELOG.md#supported-release-600

Allow `puppetlabs/stdlib` 6.x

7c8bf65 removed the use of this module.
It's not listed as a dependency either so it can be safely removed as a
fixture.

This module exclusively uses mocha mocks so it's easier to make that
explicit.

modulesync 2.7.0

We already store REFERENCE.md which contains the same information
and doesn't pollute the repository with many generated files.

Release 2.0.0