Previously, on upgrades to Sensu that installed a new embedded Ruby
installation, there was a chance that plugins installed with the `sensu_gem`
package provider would be evaluated BEFORE the Sensu package was upgraded
(which would mean that a second run of Puppet was necessary to get the plugins
installed into the new embedded Ruby installation). This commit adds a resource
chain ensuring that a change to the Sensu package will come before any package
resources using the `sensu_gem` provider (which would in turn notify the Sensu
services of their change).

This commit adds a script that will allow you to replicate and check for the
problem where plugins may get installed before a sensu package change. Note
that I have hardcoded version '0.23.0' as an 'older' version of Sensu because
I know it uses a different Ruby MRI than Latest. This may need adjusted later.

Tests were failing because of this stanza (and specifically the last line):

```puppet
Package['sensu'] ~>
Package<| provider == 'sensu_gem' |> ~>
Service['sensu-client', 'sensu-server', 'sensu-api']
```

On cases where the api or client hasn't been installed there won't be any
resources for the sensu-api or sensu-client service. In its place is this line:

```puppet
~> Service<| title == 'sensu-client' or title == 'sensu-server' or title == 'sensu-api'|>
```

That collector will discover the resources if they're there and setup the
dependencies, or exit silently if they're not in the catalog. It's not the
prettiest, but it will do.

[542] Add dependencies for sensu_gem plugins