align cert CN and SAN with app gateway listener hostname (#90)

Co-authored-by: GitHub Copilot (Claude Opus 4.6) <noreply@github.com>

Author: ferantivero

README.md

@@ -140,7 +140,7 @@ The following steps are required to deploy the infrastructure from the command l
      Create the certificate that will be presented to web clients by Azure Application Gateway for your domain.
 
      ```bash
-     openssl req -x509 -nodes -days 365 -newkey rsa:2048 -out appgw.crt -keyout appgw.key -subj "/CN=${DOMAIN_NAME_APPSERV}/O=Contoso" -addext "subjectAltName = DNS:${DOMAIN_NAME_APPSERV}" -addext "keyUsage = digitalSignature" -addext "extendedKeyUsage = serverAuth"
+     openssl req -x509 -nodes -days 365 -newkey rsa:2048 -out appgw.crt -keyout appgw.key -subj "/CN=www.${DOMAIN_NAME_APPSERV}/O=Contoso" -addext "subjectAltName = DNS:www.${DOMAIN_NAME_APPSERV}" -addext "keyUsage = digitalSignature" -addext "extendedKeyUsage = serverAuth"
      openssl pkcs12 -export -out appgw.pfx -in appgw.crt -inkey appgw.key -passout pass:
      ```