[Native] Add java plugin dependency to Konan plugin

Change required version of Gradle to 6.7

kotlin-native/endorsedLibraries/build.gradle

@@ -3,7 +3,7 @@ import org.jetbrains.kotlin.gradle.plugin.konan.tasks.KonanCacheTask
 import org.jetbrains.kotlin.EndorsedLibraryInfo
 import org.jetbrains.kotlin.UtilsKt
 
-apply plugin: 'java'
+apply plugin: 'konan'
 
 buildscript {
     repositories {

kotlin-native/platformLibs/build.gradle

@@ -25,7 +25,6 @@ ext.setProperty("org.jetbrains.kotlin.native.home", konanHome)
 ext.setProperty("konan.jvmArgs", jvmArgs)
 
 apply plugin: 'konan'
-apply plugin: 'java'
 
 //#region Util functions.
 private ArrayList<DefFile> targetDefFiles(KonanTarget  target) {

kotlin-native/tools/kotlin-native-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/konan/KonanPlugin.kt

@@ -311,7 +311,7 @@ class KonanPlugin @Inject constructor(private val registry: ToolingModelBuilderR
 
         internal const val KONAN_EXTENSION_NAME = "konan"
 
-        internal val REQUIRED_GRADLE_VERSION = GradleVersion.version("4.7")
+        internal val REQUIRED_GRADLE_VERSION = GradleVersion.version("6.7")
     }
 
     private fun Project.cleanKonan() = project.tasks.withType(KonanBuildingTask::class.java).forEach {
@@ -330,6 +330,7 @@ class KonanPlugin @Inject constructor(private val registry: ToolingModelBuilderR
     override fun apply(project: ProjectInternal) {
         checkGradleVersion()
         project.plugins.apply("base")
+        project.plugins.apply("java")
         // Create necessary tasks and extensions.
         project.tasks.create(KONAN_DOWNLOAD_TASK_NAME, KonanCompilerDownloadTask::class.java)
         project.extensions.create(KONAN_EXTENSION_NAME, KonanExtension::class.java)