kotlin v bump

Author: mvysny

build.gradle.kts

@@ -2,7 +2,7 @@ import org.gradle.api.tasks.testing.logging.TestExceptionFormat
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
-    kotlin("jvm") version "1.7.20"
+    kotlin("jvm") version "1.7.21"
     id("com.vaadin") version "23.2.7" apply(false)
     `maven-publish`
     signing