Update metadata related logic after switch to 1.6

compiler/backend/src/org/jetbrains/kotlin/codegen/state/GenerationState.kt

@@ -405,8 +405,8 @@ class GenerationState private constructor(
             this[KOTLIN_1_2] = oldMetadataVersion
             this[KOTLIN_1_3] = oldMetadataVersion
             this[KOTLIN_1_4] = JvmMetadataVersion(1, 4, 3)
-            this[KOTLIN_1_5] = JvmMetadataVersion.INSTANCE
-            this[KOTLIN_1_6] = JvmMetadataVersion(1, 6, 0)
+            this[KOTLIN_1_5] = JvmMetadataVersion(1, 5, 1)
+            this[KOTLIN_1_6] = JvmMetadataVersion.INSTANCE
             this[KOTLIN_1_7] = JvmMetadataVersion(1, 7, 0)
 
             check(size == LanguageVersion.values().size) {

core/metadata.jvm/src/org/jetbrains/kotlin/metadata/jvm/deserialization/JvmMetadataVersion.kt

@@ -26,7 +26,7 @@ class JvmMetadataVersion(versionArray: IntArray, val isStrictSemantics: Boolean)
 
     companion object {
         @JvmField
-        val INSTANCE = JvmMetadataVersion(1, 5, 1)
+        val INSTANCE = JvmMetadataVersion(1, 6, 0)
 
         @JvmField
         val INVALID_VERSION = JvmMetadataVersion()

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/sources/DefaultLanguageSettingsBuilder.kt

@@ -162,7 +162,8 @@ private val apiVersionValues = ApiVersion.run {
         KOTLIN_1_2,
         KOTLIN_1_3,
         KOTLIN_1_4,
-        KOTLIN_1_5
+        KOTLIN_1_5,
+        KOTLIN_1_6
     )
 }