Azure MSIX Build and Package task only has Release and Debug configurations

I have an Azure build pipeline that is using the MSIX Packaging suite of packages from Microsoft, which can be found here.

I am configuring the MSIX build and package task and in it there is a drop down menu for the Configuration, which only contains options for debug and release.

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However, we only have build configurations for debug, demo, development, and production and we are using SlowCheetah to identify which appsettings.<environment>.json file to use. So, we need to be able to add these additional build configurations so that the correct appsettings.json file is used. How can we add these build configurations?