add doco

org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/npm/BasePackageCacheManager.java

@@ -85,6 +85,8 @@ public abstract class BasePackageCacheManager implements IPackageCacheManager {
     return null;
   }
 
+  // hack - we have a hacked 1.4.0 out there. Only packages2.fhir.org has it.
+  // this is not a long term thing
   private boolean okToUsePackageServer(String server, String id) {
     if ("http://packages.fhir.org".equals(server) && "hl7.fhir.r2b.core".equals(id)) {
       return false;