build(deps-dev): bump electron from 12.0.6 to 15.3.1 in /src

Bumps [electron](https://github.com/electron/electron) from 12.0.6 to 15.3.1.
- [Release notes](https://github.com/electron/electron/releases)
- [Changelog](https://github.com/electron/electron/blob/main/docs/breaking-changes.md)
- [Commits](electron/electron@v12.0.6...v15.3.1)

---
updated-dependencies:
- dependency-name: electron
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

src/package.json

@@ -207,7 +207,7 @@
     "copy-webpack-plugin": "^8.1.1",
     "copyfiles": "2.4.1",
     "deepmerge": "4.2.2",
-    "electron": "^12.0.6",
+    "electron": "^15.3.1",
     "eslint": "7.26.0",
     "html-loader": "2.1.2",
     "minimist": "1.2.5",