Add a more verbose module description

[DennisL68]

When searching for foreach or foreach parallel on PSGallery, this module isn't part of the results.

A better module description might be using the first line of the repo ReadMe...

PSParallelPipeline is a PowerShell Module that includes Invoke-Parallel, a cmdlet that allows for parallel processing of input objects, sharing similar capabilities as [ForEach-Object -Parallel](https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/foreach-object) introduced in PowerShell v7.0.