Import Apache Collections models in ExternalFlow

Author: owen-mc

java/ql/src/semmle/code/java/dataflow/ExternalFlow.qll

@@ -78,6 +78,7 @@ private import FlowSummary
 private module Frameworks {
   private import internal.ContainerFlow
   private import semmle.code.java.frameworks.ApacheHttp
+  private import semmle.code.java.frameworks.apache.Collections
   private import semmle.code.java.frameworks.apache.Lang
   private import semmle.code.java.frameworks.guava.Guava
   private import semmle.code.java.frameworks.jackson.JacksonSerializability