Update conversations-entity-categories.md

Adding Driver's license and Medicare Beneficiary Identifier to Numeric Identifier examples

Author: renaaliu

articles/ai-services/language-service/personally-identifiable-information/concepts/conversations-entity-categories.md

@@ -154,6 +154,8 @@ This category contains the following entities:
         Any numeric or alphanumeric identifier that could contain any PII information. 
         Examples:   
             * Case Number 
+            * Driver's license
+            * Medicare Beneficiary Identifier (MBI)
             * Member Number 
             * Ticket number 
             * Bank account number