upgrade gradle version to 6.3

build.gradle

@@ -1,3 +1,10 @@
+plugins {
+    id 'org.springframework.boot' version '2.3.0.RELEASE'
+    id 'java'
+}
+
+apply plugin: 'io.spring.dependency-management'
+
 apply plugin: 'java'
 apply plugin: 'eclipse'
 
@@ -8,13 +15,20 @@ repositories {
     mavenCentral()
 }
 
+ext {
+    springVersion = '5.2.6.RELEASE'
+}
+
 dependencies {
     implementation 'com.google.guava:guava:29.0-jre'
     implementation 'ch.qos.logback:logback-classic:1.2.3'
     implementation 'com.github.jknack:handlebars:4.2.0'
-    implementation 'org.springframework:spring-core:5.2.6.RELEASE'
+    implementation 'org.springframework.boot:spring-boot-starter-web'
     testImplementation 'org.junit.jupiter:junit-jupiter:5.6.2'
     testImplementation 'org.assertj:assertj-core:3.16.1'
+    testImplementation('org.springframework.boot:spring-boot-starter-test') {
+        exclude group: 'junit'
+    }
 }
 
 test {

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,5 @@
-#Thu Jul 11 12:58:42 KST 2019
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip

src/test/java/webserver/ExecutorsTest.java

@@ -2,6 +2,7 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.boot.test.web.client.TestRestTemplate;
 import org.springframework.util.StopWatch;
 
 import java.util.concurrent.ExecutorService;