Fix SpotBugs [ERROR]

Medium: Class org.apache.commons.logging.impl.WeakHashtable defines non-transient non-serializable instance field queue [org.apache.commons.logging.impl.WeakHashtable] In WeakHashtable.java SE_BAD_FIELD

src/main/java/org/apache/commons/logging/impl/WeakHashtable.java

@@ -265,7 +265,7 @@ public final class WeakHashtable extends Hashtable {
     private static final int PARTIAL_PURGE_COUNT     = 10;
 
     /** ReferenceQueue we check for GC'd keys. */
-    private final ReferenceQueue queue = new ReferenceQueue();
+    private final transient ReferenceQueue queue = new ReferenceQueue();
 
     /** Counter used to control how often we purge gc'd entries. */
     private int changeCount;