Upgrade build to: Kotlin 1.9.10, Gradle 8.x, JUnit 5.10.0

Kotlin/build.gradle.kts

@@ -1,7 +1,7 @@
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
-	kotlin("jvm") version "1.8.10"
+	kotlin("jvm") version "1.9.10"
 }
 
 group = "com.gildedrose"
@@ -13,7 +13,7 @@ repositories {
 
 dependencies {
 	implementation(kotlin("stdlib"))
-	testImplementation("org.junit.jupiter:junit-jupiter:5.9.2")
+	testImplementation("org.junit.jupiter:junit-jupiter:5.10.0")
 }
 
 tasks.test {
@@ -27,3 +27,8 @@ tasks.test {
 tasks.withType<KotlinCompile>().configureEach {
 	kotlinOptions.jvmTarget = "1.8"
 }
+
+// config java extension to same target version, to avoid build failure on Gradle 8.x
+java {
+	targetCompatibility = JavaVersion.VERSION_1_8
+}