Bump spectron from 3.8.0 to 8.0.0

Bumps [spectron](https://github.com/electron/spectron) from 3.8.0 to 8.0.0.
- [Release notes](https://github.com/electron/spectron/releases)
- [Changelog](https://github.com/electron-userland/spectron/blob/master/CHANGELOG.md)
- [Commits](https://github.com/electron/spectron/compare/v3.8.0...v8.0.0)

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

package.json

@@ -116,7 +116,7 @@
     "multispinner": "^0.2.1",
     "node-loader": "^0.6.0",
     "require-dir": "^0.3.0",
-    "spectron": "^3.7.1",
+    "spectron": "^8.0.0",
     "style-loader": "^0.18.2",
     "stylus": "^0.54.5",
     "stylus-loader": "^3.0.1",