Bump electron from 5.0.7 to 6.0.4

Bumps [electron](https://github.com/electron/electron) from 5.0.7 to 6.0.4.
- [Release notes](https://github.com/electron/electron/releases)
- [Commits](https://github.com/electron/electron/compare/v5.0.7...v6.0.4)

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

package.json

@@ -15,7 +15,7 @@
     "core-js": "^3.2.0",
     "cross-env": "5.2.0",
     "css-loader": "3.2.0",
-    "electron": "^5.0.7",
+    "electron": "^6.0.4",
     "electron-builder": "^21.0.8",
     "electron-installer-snap": "^4.0.0",
     "electron-notarize": "^0.1.1",