Bump core-js from 3.7.0 to 3.8.1

Bumps [core-js](https://github.com/zloirock/core-js) from 3.7.0 to 3.8.1.
- [Release notes](https://github.com/zloirock/core-js/releases)
- [Changelog](https://github.com/zloirock/core-js/blob/master/CHANGELOG.md)
- [Commits](zloirock/core-js@v3.7.0...v3.8.1)

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

Author: dependabot[bot]