Link checks on pdk doc link to external expiring page

[pmcmaw]

Problem:

Currently https://puppet.com/docs/pdk/2.x/pdk_testing.html links to http://puppet-lint.com/ which is not owned by puppet and not only is out of date with broken links will most likely expire in next month.

Suggested improvement:

https://puppet.com/docs/pdk/2.x/pdk_testing.html

Current text :

Puppet Lint style validation. http://puppet-lint.com/

Suggested improvement:

Puppet Lint style validation. [https://github.com/puppetlabs/puppet-lint/tree/gh-pages] or a github page made from this or a new page in docs from this content

Summary:

We need to link to our fork of the link checks in whatever format is most appropriate

This bug was initially logged in JIRA, I have copied and pasted the contents from https://tickets.puppetlabs.com/browse/DOC-5155