Missing documentation for versioning

### Description

> A brief description of the Documentation Improvement or New Section request.

The file `src/scancode_config.py` says:

```
# See https://scancode-toolkit.readthedocs.io/en/latest/misc/versioning.html
# for more information on the data format version
```

but this link doesn't work. There is a scancode versioning page at:

https://scancode-toolkit.readthedocs.io/en/stable/explanation/scancode-versioning.html

but this doesn't mention anything about changes to the data format.

### Link to Documentation Page

> Where the confusion/inconsistency/incomplete documentation is.

### Select Category

- [X] Inconsistency
- [ ] New Section Request
- [ ] General Improvement
- [ ] Typo/Mistakes
- [ ] Other