Update @fortawesome/free-solid-svg-icons requirement from 5.6.1 to 5.6.3 (#3754)

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/5.6.3

)

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