Releasing WALS as CLDF dataset

Run

cldfbench makecldf cldfbench_wals.py --glottolog-version v5.0

Run
```
cldfbench cldfreadme cldfbench_wals.py
```
Run
```
cldfbench readme cldfbench_wals.py
```
Run
```
cldfbench zenodo cldfbench_wals.py
```
Run pytest
Update CHANGES.md
Commit all
Tag release