Change / to \\

Small change just to prevent user feedback like below with both slashes \ /

\Temp\build0b7c876bad0e6bc5f496819d337cc566.spiffs/virginSoil.spiffs.bin

Author: Onno-Dirkzwager

src/ESP8266FS.java

@@ -260,7 +260,7 @@ private void createAndUpload(){
     String dataPath = dataFolder.getAbsolutePath();
     String toolPath = tool.getAbsolutePath();
     String sketchName = editor.getSketch().getName();
-    String imagePath = getBuildFolderPath(editor.getSketch()) + "/" + sketchName + ".spiffs.bin";
+    String imagePath = getBuildFolderPath(editor.getSketch()) + "\\" + sketchName + ".spiffs.bin";
     String resetMethod = BaseNoGui.getBoardPreferences().get("upload.resetmethod");
     String uploadSpeed = BaseNoGui.getBoardPreferences().get("upload.speed");
     String uploadAddress = BaseNoGui.getBoardPreferences().get("build.spiffs_start");