Add 'Description' to module manifest

[anmenaga]

Upload to PS Gallery fails;
'Description' field needs to be added to module manifest:

Publish-Module : Module 'Microsoft.PowerShell.Archive' cannot be published because it is missing required metadata.
Verify that the module manifest specifies Description and Author.

PS. FYI. Running Publish-Module with -WhatIf helps detect such problems before wasting time with signing a module that can't be uploaded.