Update GitHub action build to use UmbPack

[Shazwazza]

Currently the Articulate build uses some custom XML parsing and building of the Umbraco package Zip file. This is done in the build.yml github action file. Ideally the build would use UmbPack https://our.umbraco.com/documentation/Extending/Packages/UmbPack/ to automate the package build and eventually deploy it.