Bug fix for Import-PSGetRepository in Windows PS (#1460)

Author: alerickson

src/Microsoft.PowerShell.PSResourceGet.psm1

@@ -25,9 +25,11 @@ function Import-PSGetRepository {
     Microsoft.PowerShell.Utility\Write-Verbose ('Found {0} registered PowerShellGet repositories.' -f $PSGetRepositories.Count)
 
     if ($PSGetRepositories.Count) {
-        $repos = $PSGetRepositories.Values |
+        $repos = @(
+            $PSGetRepositories.Values |
             Microsoft.PowerShell.Core\Where-Object {$_.PackageManagementProvider -eq 'NuGet'-and $_.Name -ne 'PSGallery'} |
             Microsoft.PowerShell.Utility\Select-Object Name, Trusted, SourceLocation
+        )
 
         Microsoft.PowerShell.Utility\Write-Verbose ('Selected {0} NuGet repositories.' -f $repos.Count)