Race condition in counting number of attempts #567 (#697)

Add version to Hibernate mapping so we get optimistic locking this solves
number of parallel calls trying to update/guess and mess with the lesson
counter

webgoat-container/src/main/java/org/owasp/webgoat/users/LessonTracker.java

@@ -54,6 +54,8 @@ public class LessonTracker {
     private final Set<Assignment> allAssignments = new HashSet<>();
     @Getter
     private int numberOfAttempts = 0;
+    @Version
+    private Integer version;
 
     private LessonTracker() {
         //JPA

webgoat-container/src/main/resources/db/container/V2__version.sql

@@ -0,0 +1 @@
+ALTER TABLE CONTAINER.LESSON_TRACKER ADD VERSION INTEGER;