Bump electron from 2.0.18 to 7.2.4

Bumps [electron](https://github.com/electron/electron) from 2.0.18 to 7.2.4.
- [Release notes](https://github.com/electron/electron/releases)
- [Changelog](https://github.com/electron/electron/blob/master/docs/breaking-changes.md)
- [Commits](https://github.com/electron/electron/compare/v2.0.18...v7.2.4)

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

package.json

@@ -18,7 +18,7 @@
     "babel-preset-env": "^1.6.1",
     "babel-preset-react": "^6.24.1",
     "babel-preset-stage-0": "^6.24.1",
-    "electron": "^2.0.18",
+    "electron": "^7.2.4",
     "electron-builder": "^20.44.4",
     "electron-reload": "^1.5.0",
     "extract-text-webpack-plugin": "^4.0.0-beta.0",