Update app-only-auth-powershell-v2.md

Author: chrisda

exchange/docs-conceptual/app-only-auth-powershell-v2.md

@@ -236,7 +236,7 @@ Create a self-signed x.509 certificate using one of the following methods:
   $mycert = New-SelfSignedCertificate -DnsName "contoso.org" -CertStoreLocation "cert:\CurrentUser\My" -NotAfter (Get-Date).AddYears(1) -KeySpec KeyExchange
 
   # Export certificate to .pfx file
-  $mycert | Export-PfxCertificate -FilePath mycert.pfx -Password $(ConvertTo-SecureString -String "P@ssw0Rd1234" -AsPlainText -Force)
+  $mycert | Export-PfxCertificate -FilePath mycert.pfx -Password (Get-Credential).password
 
   # Export certificate to .cer file
   $mycert | Export-Certificate -FilePath mycert.cer