Bump rollup-plugin-sourcemaps from 0.6.2 to 0.6.3

Bumps [rollup-plugin-sourcemaps](https://github.com/maxdavidson/rollup-plugin-sourcemaps) from 0.6.2 to 0.6.3.
- [Release notes](https://github.com/maxdavidson/rollup-plugin-sourcemaps/releases)
- [Changelog](https://github.com/maxdavidson/rollup-plugin-sourcemaps/blob/master/CHANGELOG.md)
- [Commits](maxdavidson/rollup-plugin-sourcemaps@v0.6.2...v0.6.3)

Signed-off-by: dependabot-preview[bot] <[email protected]>