Compile kotlinx-metadata-jvm with JVM target 1.6 instead of 1.8

#KT-25920 Fixed

libraries/kotlinx-metadata/build.gradle.kts

@@ -4,6 +4,9 @@ plugins {
     kotlin("jvm")
 }
 
+jvmTarget = "1.6"
+javaHome = rootProject.extra["JDK_16"] as String
+
 sourceSets {
     "main" { projectDefault() }
     "test" { }

libraries/kotlinx-metadata/jvm/ChangeLog.md

@@ -2,6 +2,7 @@
 
 ## 0.0.4
 
+- [`KT-25920`](https://youtrack.jetbrains.com/issue/KT-25920) Compile kotlinx-metadata-jvm with JVM target bytecode version 1.6 instead of 1.8
 - [`KT-25223`](https://youtrack.jetbrains.com/issue/KT-25223) Add JvmFunctionExtensionVisitor.visitEnd
 
 ## 0.0.3

libraries/kotlinx-metadata/jvm/build.gradle.kts

@@ -20,6 +20,9 @@ group = "org.jetbrains.kotlinx"
 val deployVersion = findProperty("kotlinxMetadataDeployVersion") as String?
 version = deployVersion ?: "0.1-SNAPSHOT"
 
+jvmTarget = "1.6"
+javaHome = rootProject.extra["JDK_16"] as String
+
 sourceSets {
     "main" { projectDefault() }
     "test" { projectDefault() }