small refactor

src/jsMain/kotlin/com/infendro/shell/Shell.js.kt

@@ -1,9 +1,9 @@
 package com.infendro.shell
 
-import kotlin.coroutines.resume
-import kotlin.coroutines.suspendCoroutine
 import node.childProcess.ExecOptions
 import node.childProcess.exec
+import kotlin.coroutines.resume
+import kotlin.coroutines.suspendCoroutine
 
 internal actual suspend fun execute(
     command: Array<String>,
@@ -13,7 +13,7 @@ internal actual suspend fun execute(
     val options = ExecOptions.invoke(cwd = directory)
     exec(command, options) { error, stdout, stderr ->
         val code = if (error == null) 0 else error.code!!.toInt()
-        val value = if (error == null) stdout else stderr
+        val value = (if (error == null) stdout else stderr) as String
         continuation.resume(Shell.Result(code, value))
     }
 }