Removes explicit setting of kotlin maven plugin version.

Fixes gh-2892

pom.xml

@@ -57,7 +57,6 @@
 		<spring-cloud-circuitbreaker.version>3.0.1-SNAPSHOT</spring-cloud-circuitbreaker.version>
 		<spring-cloud-commons.version>4.0.2-SNAPSHOT</spring-cloud-commons.version>
 		<testcontainers.version>1.17.3</testcontainers.version>
-		<kotlin-maven-plugin.version>1.6.21</kotlin-maven-plugin.version>
 	</properties>
 
 	<dependencyManagement>

spring-cloud-gateway-sample/pom.xml

@@ -95,7 +95,6 @@
 			<plugin>
 				<groupId>org.jetbrains.kotlin</groupId>
 				<artifactId>kotlin-maven-plugin</artifactId>
-				<version>${kotlin-maven-plugin.version}</version>
 				<configuration>
 					<args>
 						<arg>-Xjsr305=strict</arg>

spring-cloud-gateway-server/pom.xml

@@ -230,7 +230,6 @@
 				<!-- Based on instructions here - https://kotlinlang.org/docs/reference/using-maven.html -->
 				<artifactId>kotlin-maven-plugin</artifactId>
 				<groupId>org.jetbrains.kotlin</groupId>
-				<version>${kotlin-maven-plugin.version}</version>
 				<configuration>
 					<jvmTarget>17</jvmTarget>
 				</configuration>