Use PowerShell parameter validation

common/Scripts/UseTargetFrameworks.ps1

@@ -1,7 +1,7 @@
-if ($args.Length -eq 0 -or ![bool]$args[0]) {
-    Write-Error "Please supply one or more arguments. Valid values are all, wasm, uwp, winappsdk, wpf, gtk, macos, ios, and droid.";
-    exit(-1);
-}
+Param (
+	[ValidateSet('all', 'wasm', 'uwp', 'winappsdk', 'wpf', 'gtk', 'macos', 'ios', 'droid')]
+	[string[]]$targets
+)
 
 if ($args.Contains("--allow-git-changes")) {
     Write-Warning "Changes to the default TargetFrameworks in Labs can now be committed. Run this command again without the --allow-git-changes flag to disable committing further changes.";
@@ -35,39 +35,39 @@ $allTargetFrameworks = @(
 
 $desiredTfmValues = @();
 
-if ($args.Contains("all")) {
+if ($targets.Contains("all")) {
     $desiredTfmValues = $allTargetFrameworks;
 }
 
-if ($args.Contains("wasm")) {
+if ($targets.Contains("wasm")) {
     $desiredTfmValues += $WasmTfm;
 }
 
-if ($args.Contains("uwp")) {
+if ($targets.Contains("uwp")) {
     $desiredTfmValues += $UwpTfm;
 }
 
-if ($args.Contains("winappsdk")) {
+if ($targets.Contains("winappsdk")) {
     $desiredTfmValues += $WinAppSdkTfm;
 }
 
-if ($args.Contains("wpf")) {
+if ($targets.Contains("wpf")) {
     $desiredTfmValues += $WpfTfm;
 }
 
-if ($args.Contains("gtk")) {
+if ($targets.Contains("gtk")) {
     $desiredTfmValues += $GtkTfm;
 }
 
-if ($args.Contains("macos")) {
+if ($targets.Contains("macos")) {
     $desiredTfmValues += $macOSTfm;
 }
 
-if ($args.Contains("ios")) {
+if ($targets.Contains("ios")) {
     $desiredTfmValues += $iOSTfm;
 }
 
-if ($args.Contains("droid")) {
+if ($targets.Contains("droid")) {
     $desiredTfmValues += $DroidTfm;
 }