Add serialVersionUID

Author: damianmalczewski

problem4j-jackson3/src/main/java/io/github/problem4j/jackson3/ProblemJacksonModule.java

@@ -21,6 +21,7 @@
 package io.github.problem4j.jackson3;
 
 import io.github.problem4j.core.Problem;
+import java.io.Serial;
 import tools.jackson.databind.module.SimpleModule;
 
 /**
@@ -37,6 +38,8 @@
  */
 public class ProblemJacksonModule extends SimpleModule {
 
+  @Serial private static final long serialVersionUID = 1L;
+
   /**
    * Creates and initializes the {@code ProblemJacksonModule}.
    *