Enablement of unified_mode for v17+ Chef client compatibility

[ChefAustin]

Describe the Enhancement:

Converging the cookbooks in this repo on a v17+ Chef client result in the following deprecation warning being thrown (using cpe_launchd as an example):

  The cpe_launchd resource in the cpe_launchd cookbook should declare `unified_mode true` at 1 location:
    - /etc/chef/local-mode-cache/cache/cookbooks/cpe_launchd/resources/cpe_launchd.rb
   See https://docs.chef.io/deprecations_unified_mode/ for further details.

https://docs.chef.io/unified_mode/

Describe the Need:

Anyone using Chef client v17+ will face this deprecation warning until unified_mode true is appended to the first line of each custom resource file.

Current Alternative

Ignore the deprecation warning.

Can We Help You Implement This?:

Should be an easy PR (or series of PR's) to craft.