refactor: remove code smell java:S5786 (#2159)

https://sonarcloud.io/organizations/iluwatar/rules?open=java%3AS5786&rule_key=java%3AS5786

template-method/src/test/java/com/iluwatar/templatemethod/StealingMethodTest.java

@@ -48,12 +48,12 @@ public abstract class StealingMethodTest<M extends StealingMethod> {
   private InMemoryAppender appender;
 
   @BeforeEach
-  public void setUp() {
+  void setUp() {
     appender = new InMemoryAppender();
   }
 
   @AfterEach
-  public void tearDown() {
+  void tearDown() {
     appender.stop();
   }