Update @fortawesome/free-solid-svg-icons requirement from 5.5.0 to 5.6.1 (#3610)
Update @fortawesome/free-solid-svg-icons requirement from 5.5.0 to 5.6.1 (#3610)

Updates the requirements on [@fortawesome/free-solid-svg-icons](https://github.com/FortAwesome/Font-Awesome) to permit the latest version.
- [Release notes](https://github.com/FortAwesome/Font-Awesome/releases)
- [Changelog](https://github.com/FortAwesome/Font-Awesome/blob/master/CHANGELOG.md)
- [Commits](https://github.com/FortAwesome/Font-Awesome/commits/5.6.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
syuilo/Misskey,syuilo/Misskey