Bump electron from 1.8.8 to 9.1.0 in /app

Bumps [electron](https://github.com/electron/electron) from 1.8.8 to 9.1.0.
- [Release notes](https://github.com/electron/electron/releases)
- [Changelog](https://github.com/electron/electron/blob/master/docs/breaking-changes.md)
- [Commits](electron/electron@v1.8.8...v9.1.0)

Signed-off-by: dependabot[bot] <support@github.com>

app/package.json

@@ -18,7 +18,7 @@
     "bluebird": "^3.4.6",
     "compressible": "^2.0.9",
     "coffeescript": "^1.12.6",
-    "electron": "^1.6.1",
+    "electron": "^9.1.0",
     "event-stream": "^3.3.4",
     "globby": "^6.1.0",
     "glsl-strip-comments": "^1.0.0",