Update to Kotlin 1.2.60 & Kotlin/Native 0.8.1
diff --git a/gradle.properties b/gradle.properties
index 5832f17..e2fc770 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,8 +1,8 @@
 version = 0.11.0-SNAPSHOT
 group = org.jetbrains.kotlinx
 
-kotlin_version = 1.2.51
-kotlin_native_version = 0.9-dev-2922
+kotlin_version = 1.2.60
+kotlin_native_version = 0.8.1
 asm_version = 5.2
 slf4j_version = 1.8.0-alpha2
 junit_version = 4.12