Update version to 4.4.0 #605

Job	Run time
Determine Version Number	8s
Test on Linux	8m 57s
Build on Linux	56s
Pack .NET Core Global Tool (CLI) and PluginAPI	35s
Run test projects on Linux (src/TestProjects/ImportAndUseNuGetPackages2021)	3m 52s
Run test projects on Linux (src/TestProjects/ImportAndUseNuGetPackages)	2m 28s
Create .unitypackage on Linux	1m 22s
	18m 18s

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