The invoke_params method does not handle datetime objects

[michaeltlombardi]

Describe the Bug

When passing a datetime string in a hash to Invoke-DscResource it fails with the following message:

Could not evaluate: Convert property 'starttime' value from type 'STRING' to type 'DATETIME' failed

This is caused by the failure of implicit casting, similar to what happens with empty arrays (see #55 for more details). Special handling should be added to the handler, as with PSCredential objects, since the value in the manifest is a string.

Expected Behavior

When a datetime parameter is specified in a manifest it does not cause casting errors when passed to Invoke-DscResource.

Steps to Reproduce

# requires dsc-computermanagementdsc
ScheduledTask { 'Test StartTime Casting':
  dsc_taskname                  => 'Test starttime casting',
  dsc_actionexecutable          => 'C:\windows\system32\WindowsPowerShell\v1.0\powershell.exe',
  dsc_scheduletype              => 'Once',
  dsc_starttime                 => '2018-10-01T01:00:00',
  dsc_enable                    => true,
}

Suggested Fix

Similar to the handling for empty arrays:

date_time_parameters = resource[:parameters].select { |k,v| v[:mof_type] ~= /DateTime/i }
date_time_parameters.each do |name, properties|
  param_block_name = name.to_s.gsub(/^dsc_/, '')
  params_block = params_block.gsub("#{param_block_name} = ", "#{param_block_name} = [#{properties[:mof_type]}]")
end