Update how-to-prerequisites.md

https://identitydivision.visualstudio.com/Engineering/_workitems/edit/1832763/

Updating URL listing for GOV cloud based on previous support case learnings, adding the missing uls bellow;
aadcdn.msftauthimages.us
*.microsoft.us 
msauthimages.us
mfstauthimages.us

Author: Renato Vieira

articles/active-directory/cloud-sync/how-to-prerequisites.md

@@ -165,7 +165,7 @@ If there's a firewall between your servers and Azure AD, configure the following
  |-----|-----|
  |&#42;.msappproxy.us</br>&#42;.servicebus.usgovcloudapi.net|The agent uses these URLs to communicate with the Azure AD cloud service. |
  |`mscrl.microsoft.us:80` </br>`crl.microsoft.us:80` </br>`ocsp.msocsp.us:80` </br>`www.microsoft.us:80`| The agent uses these URLs to verify certificates.|
- |login.windows.us </br>secure.aadcdn.microsoftonline-p.com </br>&#42;.microsoftonline.us </br>&#42;.microsoftonline-p.us </br>&#42;.msauth.net </br>&#42;.msauthimages.net </br>&#42;.msecnd.net</br>&#42;.msftauth.net </br>&#42;.msftauthimages.net</br>&#42;.phonefactor.net </br>enterpriseregistration.windows.net</br>management.azure.com </br>policykeyservice.dc.ad.msft.net</br>ctldl.windowsupdate.us:80| The agent uses these URLs during the registration process.
+ |login.windows.us </br>secure.aadcdn.microsoftonline-p.com </br>&#42;.microsoftonline.us </br>&#42;.microsoftonline-p.us </br>&#42;.msauth.net </br>&#42;.msauthimages.net </br>&#42;.msecnd.net</br>&#42;.msftauth.net </br>&#42;.msftauthimages.net</br>&#42;.phonefactor.net </br>enterpriseregistration.windows.net</br>management.azure.com </br>policykeyservice.dc.ad.msft.net</br>ctldl.windowsupdate.us:80 </br>aadcdn.msftauthimages.us </br>*.microsoft.us </br>msauthimages.us </br>mfstauthimages.us| The agent uses these URLs during the registration process.