fix tslint issue

Author: Sneezry

src/arduino/arduinoSettings.ts

@@ -63,8 +63,8 @@ export class ArduinoSettings implements IArduinoSettings {
 
         // Arduino IDE will save all packages into portable folder if it exsits.
         // https://github.com/Microsoft/vscode-arduino/issues/415
-        if (!util.directoryExistsSync(this._packagePath) && util.directoryExistsSync(path.join(this._arduinoPath, 'portable'))) {
-            this._packagePath = path.join(this._arduinoPath, 'portable');
+        if (!util.directoryExistsSync(this._packagePath) && util.directoryExistsSync(path.join(this._arduinoPath, "portable"))) {
+            this._packagePath = path.join(this._arduinoPath, "portable");
         }
     }