Add Customer Identifier Type for Alumni customers

composer.json

 {
   "name": "adi-ia/cbs-techstore-client-php",
   "description": "A PHP client used to connect with the CBS API and perform requests",
-  "version": "6.2.3",
+  "version": "6.3.0",
   "license": "Apache-2.0",
   "homepage": "https://wiki.doit.wisc.edu/confluence/display/ADIIA/CBS",
   "authors": [

src/main/edu/wisc/services/cbs/common/MagentoOrder.php

@@ -30,6 +30,9 @@ abstract class MagentoOrder
     /** @var string Type of identifier for SOAR Parent orders */
     const SOAR_PARENT_IDENTIFIER_TYPE = 'SoarParent';
 
+    /** @var string Type of identifier for Alumni orders */
+    const ALUMNI_IDENTIFIER_TYPE = 'Alumni';
+
     /** @var string Payment type for credit card orders */
     const CREDIT_CARD_IDENTIFIER_TYPE = 'CREDIT CARD';