Update DIRECTORY.md

Author: alxkm

DIRECTORY.md

@@ -1128,6 +1128,7 @@
           - 📄 [EdmondsKarpTest](src/test/java/com/thealgorithms/graph/EdmondsKarpTest.java)
           - 📄 [EdmondsTest](src/test/java/com/thealgorithms/graph/EdmondsTest.java)
           - 📄 [HopcroftKarpTest](src/test/java/com/thealgorithms/graph/HopcroftKarpTest.java)
+          - 📄 [HungarianAlgorithmTest](src/test/java/com/thealgorithms/graph/HungarianAlgorithmTest.java)
           - 📄 [PredecessorConstrainedDfsTest](src/test/java/com/thealgorithms/graph/PredecessorConstrainedDfsTest.java)
           - 📄 [PushRelabelTest](src/test/java/com/thealgorithms/graph/PushRelabelTest.java)
           - 📄 [StronglyConnectedComponentOptimizedTest](src/test/java/com/thealgorithms/graph/StronglyConnectedComponentOptimizedTest.java)