Zipping a single file with PowerShell

I recently needed to quickly create a PowerShell script that would create a Zip file from a specified input file.  A quick Bing search found a popular solution on StackOverflow: function ZipFiles( $zipfilename, $sourcedir ){     Add-Type -Assembly System.IO.Compression.FileSystem      $compressionLevel = [System.IO.Compression.CompressionLevel]::Optimal     [System.IO.Compression.ZipFile]::CreateFromDirectory($sourcedir,                                                           $zipfilename,                                                          $compressionLevel,                                                           $false) } Unfortunately, this would not work for me.  This script zips everything in…