added missing @since tag in isFrozen() method javadoc

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/chain/branches/version-2.0-work@1165395 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/commons/chain/impl/ChainBase.java b/src/main/java/org/apache/commons/chain/impl/ChainBase.java
index efac659..6558490 100644
--- a/src/main/java/org/apache/commons/chain/impl/ChainBase.java
+++ b/src/main/java/org/apache/commons/chain/impl/ChainBase.java
@@ -234,6 +234,7 @@
      * @return true, if the configuration of our commands list
      * has been frozen by a call to the <code>execute()</code> method,
      * false otherwise.
+     * @since 3.0
      */
     public boolean isFrozen() {
         return frozen;