Replace myget with Azure artifacts (#14543)

Author: dingmeng-xue

NuGet.Config

@@ -4,7 +4,7 @@
     <clear/>
     <!-- Do not add any additional feeds if new packages are needed they need to come from nuget.org or our azure-sdk-for-net DevOps feed -->
     <add key="local-feed" value="tools/LocalFeed" />
-    <add key="myget-azure-powershell" value="https://www.myget.org/F/azure-powershell/api/v3/index.json" />
+    <add key="azure-powershell" value="https://pkgs.dev.azure.com/azure-sdk/public/_packaging/azure-powershell/nuget/v3/index.json" />
     <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
   </packageSources>
   <disabledPackageSources>