Using Azure Powershell or the xpat cli how do I connect my web site to a github hook

Depending on your use case the solution will be different.

1. Assuming you have the same github source but want to deploy to multiple different Azure websitesPotential Solution: Make use of the Deploy to Azure Button See details here: https://azure.microsoft.com/blog/2014/11/13/deploy-to-azure-button-for-azure-websites-2/

2. Assuming you have various repositories that you want to deploy to Azure: Potential Solution: I am assuming that you will be the person deploying it. The workflow will be as follows:

   A. Download files from Github to local folder See here

   B. Publish your local folder into a new/existing Azure site. See here, or here. There are other github repositories to get some scripts right away

I understand this doesnt directly hook your system to do direct pull, but its one way to do it.
There is also:

http://www.imtraum.com/blog/streamline-git-with-powershell/https://gallery.technet.microsoft.com/scriptcenter/a-GitHub-Repository-265c0b49

Both documents I found describing how to set up continuous deployment from GitHub say that you can configure the repo and branch with an Azure Resource Manager template, but you have to enter your credentials and complete the authorization process in the portal.

The script used in this tutorial will automatically configure continuous publishing from your GitHub repository. This requires that your GitHub credentials are already stored in Azure, otherwise the scripted deployment will fail when attempting to configure source control settings for the web apps.

To store your GitHub credentials in Azure, create a web app in the Azure preview portal and configure GitHub deployment. You only need to do this once.

I'd also suggest posting your xpat-cli problem as an issue on their GitHub repo.