Chore: JUnit 의존성 추가

build.gradle

@@ -50,6 +50,7 @@ dependencies {
     runtimeOnly 'com.mysql:mysql-connector-j'
     annotationProcessor 'org.projectlombok:lombok'
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
+    testImplementation 'junit:junit:4.13.2'
     testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
 }