chore: Update JUnit 4 -> 6

Author: jentfoo

build.gradle

@@ -17,7 +17,8 @@ repositories {
 }
 
 dependencies {
-  testImplementation 'junit:junit:4.13.2'
+  testImplementation 'org.junit.jupiter:junit-jupiter:6.0.3'
+  testRuntimeOnly 'org.junit.platform:junit-platform-launcher:6.0.3'
   implementation "org.threadly:threadly:$threadlyVersion"
 }
 
@@ -36,6 +37,8 @@ checkstyle {
 def testMode = project.findProperty('testMode') ?: 'default'
 
 test {
+  useJUnitPlatform()
+
   switch (testMode) {
     case 'slow':
       maxParallelForks = 1

src/test/java/org/threadly/Repeat.java

@@ -2,7 +2,6 @@
 
 import java.lang.Thread.UncaughtExceptionHandler;
 
-import org.junit.Rule;
 import org.threadly.util.ExceptionHandler;
 import org.threadly.util.ExceptionUtils;
 import org.threadly.util.StringUtils;
@@ -131,9 +130,6 @@ public static void setIgnoreExceptionHandler() {
     ExceptionUtils.setDefaultExceptionHandler(ieh);
   }
 
-  @Rule
-  public RepeatRule repeatRule = new RepeatRule();
-  
   private static class IgnoreExceptionHandler implements UncaughtExceptionHandler, 
                                                          ExceptionHandler {
     @Override