Update FontAwesome to 6.7.1. (#943)

### Prerequisites

Put an `x` into the box(es) that apply:

- [x] This pull request fixes a bug.
- [x] This pull request adds a feature.
- [ ] This pull request introduces breaking change.

### Description

https://fontawesome.com/changelog

See changelogs for 6.7.0 and 6.7.1.

This includes additional icons and tweaks for the formatting of some
existing icons. These files are directly unpacked, without any
modification, from the published free ZIP file on the FA github and on
FA's own website.

### Issues Resolved

N/A

### Checklist

Put an `x` into the box(es) that apply:

#### General

- [x] Describe what changes are being made
- [x] Explain why and how the changes were necessary and implemented
respectively
- [ ] Reference issue with `#<ISSUE_NO>` if applicable

#### Resources

- [x] If you have changed any SCSS code, run `make release` to
regenerate all CSS files

#### Contributors

- [ ] Add yourself to `CONTRIBUTORS.md` if you aren't on it already

Co-authored-by: Luiz F. A. de Prá <luizdepra@users.noreply.github.com>