Use platform dependencies instead of the dependency management plugin

Closes gh-42712

spring-boot-tests/spring-boot-integration-tests/spring-boot-server-tests/spring-boot-server-tests-app/build.gradle

@@ -7,8 +7,6 @@ plugins {
 	id "war"
 }
 
-apply plugin: "io.spring.dependency-management"
-
 repositories {
 	maven { url "file:${rootDir}/../test-repository"}
 	mavenCentral()
@@ -50,6 +48,7 @@ dependencies {
 	compileOnly("org.eclipse.jetty.ee10:jetty-ee10-servlet")
 	compileOnly("org.springframework:spring-web")
 
+	implementation(platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES))
 	implementation("org.springframework.boot:spring-boot-starter")
 
 	app(files(resourcesJar))