Bump source-map-loader from 0.2.3 to 0.2.4

Bumps [source-map-loader](https://github.com/webpack-contrib/source-map-loader) from 0.2.3 to 0.2.4.
- [Release notes](https://github.com/webpack-contrib/source-map-loader/releases)
- [Changelog](https://github.com/webpack-contrib/source-map-loader/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/source-map-loader@v0.2.3...v0.2.4)

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

Author: dependabot-support