Update ZVML-simple-list-vpgs.ps1

Add doc link

ZVML-simple-list-vpgs.ps1

@@ -7,6 +7,8 @@ In no event shall Zerto, its authors or anyone else involved in the creation, pr
 
 # Notes:
 # - requires ZVM Linux Appliance 9.5U1 or higher, developed and tested on 9.5U3
+# - Relevant Documentation: 
+#     - Obtaining a Keycloak Token to Use in API Tools: https://help.zerto.com/bundle/Linux.ZVM.HTML/page/Keycloak_token_for_API_tools.htm
 
 # Variables to Configure
 
@@ -80,4 +82,4 @@ catch {
     Write-Error "Error making API call to ZVM" -ErrorAction Stop
 }
 
-$result | select VPGName,VMsCount, SourceSite, TargetSite, ActualRPO | format-table
+$result | select VPGName,VMsCount, SourceSite, TargetSite, ActualRPO | format-table