Upgrade to Kotlin 1.2.71

Closes gh-14766

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

@@ -123,7 +123,7 @@
 		<junit.version>4.12</junit.version>
 		<junit-jupiter.version>5.3.1</junit-jupiter.version>
 		<kafka.version>2.0.0</kafka.version>
-		<kotlin.version>1.2.70</kotlin.version>
+		<kotlin.version>1.2.71</kotlin.version>
 		<lettuce.version>5.1.0.RELEASE</lettuce.version>
 		<liquibase.version>3.6.2</liquibase.version>
 		<log4j2.version>2.11.1</log4j2.version>