Use app-builder-lib to get electron version (#288)

So we can get it the same way electron-builder does and not need
electronVersion in package.json

package.json

@@ -55,6 +55,7 @@
     "@typescript-eslint/eslint-plugin": "^4.17.0",
     "@typescript-eslint/parser": "^4.17.0",
     "allchange": "^1.0.6",
+    "app-builder-lib": "^22.14.10",
     "asar": "^2.0.1",
     "chokidar": "^3.5.2",
     "electron": "13.5",
@@ -83,7 +84,6 @@
   },
   "build": {
     "appId": "im.riot.app",
-    "electronVersion": "13.5.2",
     "files": [
       "package.json",
       {