Bump webpack-merge from 4.1.2 to 4.1.3 in /apps/updatenotification

Bumps [webpack-merge](https://github.com/survivejs/webpack-merge) from 4.1.2 to 4.1.3.
- [Release notes](https://github.com/survivejs/webpack-merge/releases)
- [Changelog](https://github.com/survivejs/webpack-merge/blob/master/CHANGELOG.md)
- [Commits](https://github.com/survivejs/webpack-merge/compare/v4.1.2...v4.1.3

)

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