Update hfst package to latest upstream release 3.16.0 in Debian.
- hfst -> 3.15.4 -> 3.16.0
- Fix license issue with upstream 3.15.4: https://github.com/hfst/hfst/issues/494
- 3.15.4: Upload to Debian: https://salsa.debian.org/science-team/hfst
- 3.16.0: Update in Salsa.
- Update foma to: 0.10.0
- Upload 3.16.0 to Debian.
- Experimental (Accepted: ✔)
- Unstable.