Replace manual dependency management by Kotlin's bom

Closes gh-9486

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -2466,33 +2466,10 @@
 			</dependency>
 			<dependency>
 				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-reflect</artifactId>
-				<version>${kotlin.version}</version>
-			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-stdlib</artifactId>
-				<version>${kotlin.version}</version>
-			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-stdlib-jdk7</artifactId>
-				<version>${kotlin.version}</version>
-			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-stdlib-jdk8</artifactId>
-				<version>${kotlin.version}</version>
-			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-stdlib-jre7</artifactId>
-				<version>${kotlin.version}</version>
-			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-stdlib-jre8</artifactId>
+				<artifactId>kotlin-bom</artifactId>
 				<version>${kotlin.version}</version>
+				<type>pom</type>
+				<scope>import</scope>
 			</dependency>
 			<dependency>
 				<groupId>org.jolokia</groupId>