fix(powershell): pass args verbatim to npm

Fixes #7375

Author: lukekarrys

bin/npm.ps1

@@ -24,9 +24,9 @@ if (Test-Path $NPM_PREFIX_NPM_CLI_JS) {
 
 # Support pipeline input
 if ($MyInvocation.ExpectingInput) {
-  $input | & $NODE_EXE $NPM_CLI_JS $args
+  $input | & $NODE_EXE $NPM_CLI_JS -- $args
 } else {
-  & $NODE_EXE $NPM_CLI_JS $args
+  & $NODE_EXE $NPM_CLI_JS -- $args
 }
 
 exit $LASTEXITCODE

test/bin/windows-shims.js

@@ -53,7 +53,7 @@ t.test('shim contents', t => {
 
   t.test('pwsh', t => {
     const { diff, letters } = diffFiles(SHIMS['npm.ps1'], SHIMS['npx.ps1'])
-    t.strictSame(diff, [])
+    t.strictSame(diff, ['-- ', '-- '], 'only npm powershell uses -- for verbatim args')
     t.strictSame([...letters], ['M', 'X'], 'all other changes are m->x')
     t.end()
   })