Fix embedded version of kotlin-stdlib in buildSrc

To avoid bringing stdlib:1.2.30, which is a transitive dependency of
com.jakewharton.dex:dex-method-list:3.0.0, into compile classpath of
the project build scripts.

buildSrc/build.gradle.kts

@@ -92,6 +92,7 @@ repositories {
 }
 
 dependencies {
+    compile(kotlin("stdlib", embeddedKotlinVersion))
     compile("net.rubygrapefruit:native-platform:${property("versions.native-platform")}")
     compile("net.rubygrapefruit:native-platform-windows-amd64:${property("versions.native-platform")}")
     compile("net.rubygrapefruit:native-platform-windows-i386:${property("versions.native-platform")}")