build(win): modify electron packaging target to portable on Windows platform to generate directly runnable exe

electron-builder.json

@@ -5,12 +5,9 @@
 
   "files": ["dist/h5/**/*", "main.js"],
   "win": {
-    "signtoolOptions": {
-      "sign": "./customSign.js"
-    },
     "target": [
       {
-        "target": "nsis",
+        "target": "portable",
         "arch": ["x64", "ia32"]
       }
     ]