Add explicit JUnit4 dep due to jackson-base refactoring

Author: cowtowncoder

pom.xml

@@ -51,6 +51,13 @@
       <groupId>com.fasterxml.jackson.core</groupId>
       <artifactId>jackson-databind</artifactId>
     </dependency>
+
+    <!-- 20-Apr-2024, tatu: JUnit4 no longer from jackson-base, so: -->
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <!-- Alas, need to include snapshot reference since otherwise can not find