Upgrade to Kotlin 1.3.21

Closes gh-16195

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

@@ -138,7 +138,7 @@
 		<junit.version>4.12</junit.version>
 		<junit-jupiter.version>5.4.0</junit-jupiter.version>
 		<kafka.version>2.1.1</kafka.version>
-		<kotlin.version>1.2.71</kotlin.version>
+		<kotlin.version>1.3.21</kotlin.version>
 		<lettuce.version>5.1.5.RELEASE</lettuce.version>
 		<liquibase.version>3.6.3</liquibase.version>
 		<log4j2.version>2.11.2</log4j2.version>
@@ -2469,11 +2469,6 @@
 				<artifactId>kotlin-reflect</artifactId>
 				<version>${kotlin.version}</version>
 			</dependency>
-			<dependency>
-				<groupId>org.jetbrains.kotlin</groupId>
-				<artifactId>kotlin-runtime</artifactId>
-				<version>${kotlin.version}</version>
-			</dependency>
 			<dependency>
 				<groupId>org.jetbrains.kotlin</groupId>
 				<artifactId>kotlin-stdlib</artifactId>

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

@@ -63,7 +63,7 @@
 			<dependency>
 				<groupId>io.mockk</groupId>
 				<artifactId>mockk</artifactId>
-				<version>1.9.1.kotlin12</version>
+				<version>1.9.1</version>
 			</dependency>
 			<dependency>
 				<groupId>org.sonatype.plexus</groupId>
@@ -287,8 +287,6 @@
 					<version>${kotlin.version}</version>
 					<configuration>
 						<jvmTarget>${java.version}</jvmTarget>
-						<apiVersion>1.1</apiVersion>
-						<languageVersion>1.1</languageVersion>
 						<javaParameters>true</javaParameters>
 					</configuration>
 				</plugin>

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

@@ -172,11 +172,6 @@
 			<artifactId>johnzon-jsonb</artifactId>
 			<scope>test</scope>
 		</dependency>
-		<dependency>
-			<groupId>org.jetbrains.kotlin</groupId>
-			<artifactId>kotlin-runtime</artifactId>
-			<scope>test</scope>
-		</dependency>
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-api</artifactId>