Add generated serial version UIDs to exceptions

src/main/java/de/epiceric/shopchest/exceptions/ChestNotFoundException.java

@@ -1,9 +1,9 @@
 package de.epiceric.shopchest.exceptions;
 
 public class ChestNotFoundException extends Exception {
+    private static final long serialVersionUID = -6446875473671870708L;
 
     public ChestNotFoundException(String message) {
         super(message);
     }
-
 }

src/main/java/de/epiceric/shopchest/exceptions/NotEnoughSpaceException.java

@@ -1,9 +1,9 @@
 package de.epiceric.shopchest.exceptions;
 
 public class NotEnoughSpaceException extends Exception {
+    private static final long serialVersionUID = 3718475607700458355L;
 
     public NotEnoughSpaceException(String message) {
         super(message);
     }
-
 }

src/main/java/de/epiceric/shopchest/exceptions/WorldNotFoundException.java

@@ -1,9 +1,9 @@
 package de.epiceric.shopchest.exceptions;
 
 public class WorldNotFoundException extends Exception {
+    private static final long serialVersionUID = -555886332156936972L;
 
     public WorldNotFoundException(String worldName) {
         super("Could not find world with name \"" + worldName + "\"");
     }
-
 }