obsolete nowarn removed from gradle.properties

Author: morisil

gradle.properties

@@ -1,7 +1,6 @@
 kotlin.code.style=official
 # TODO the next line can be removed for a non-library project
 kotlin.js.generate.executable.default=false
-kotlin.apple.xcodeCompatibility.nowarn=true
 # TODO the next line can be removed for a non-library project
 kotlin.experimental.swift-export.enabled=true
 kotlin.native.enableKlibsCrossCompilation=true