Update ServiceRegistry class to make getAllServiceAddresses static method

registration-discovery-leader-reelection-cordinator-workers/src/main/java/Registration_Discovery/ServiceRegistry.java

@@ -17,9 +17,9 @@ public class ServiceRegistry implements Watcher {
     private final ZooKeeper zooKeeper;
 
     private String currentZnode = null;
-    private List<String> allServiceAddresses = null;
+    private static List<String> allServiceAddresses = null;
 
-    public List<String> getAllServiceAddresses() {
+    public static List<String> getAllServiceAddresses() {
         return allServiceAddresses;
     }