Fixes puppetlabs-docker module for registry configuration
Fixes puppetlabs-docker module for registry configuration

When an authenticated registry is added, a file is created based on the
registry URL. Since this URL can contain `/`, this caused an error as
puppet interpreted these `/` as a change in directory.

Now the filename uses a stripped version of the registry URL:

```
$server_strip = regsubst($server, '/', '_', 'G')
```

This fix is also included in the version [3.12.1]
(https://forge.puppet.com/puppetlabs/docker)

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet