Update Batch psd1 required assemblies

Author: matthchr

src/Batch/Batch/Az.Batch.psd1

@@ -61,7 +61,9 @@ RequiredAssemblies = '.\Microsoft.Azure.Batch.dll',
                '.\Microsoft.Extensions.Primitives.dll', 
                '.\System.Runtime.CompilerServices.Unsafe.dll', 
                '.\Microsoft.WindowsAzure.Storage.dll', 
-               '.\Microsoft.AspNetCore.WebUtilities.dll'
+               '.\Microsoft.AspNetCore.WebUtilities.dll',
+               '.\Microsoft.Net.Http.Headers.dll',
+               '.\System.Text.Encodings.Web.dll'
 
 # Script files (.ps1) that are run in the caller's environment prior to importing this module.
 # ScriptsToProcess = @()