Enable more version of the docs

[Coffee2CodeNL]

This is:

- [ ] a bug report
- [X] a feature request
- [ ] **not** a usage question (ask them on https://stackoverflow.com/questions/tagged/phpspreadsheet or https://gitter.im/PHPOffice/PhpSpreadsheet)

What is the expected behavior?

Have docs for all tags in this repo

What is the current behavior?

There's only docs available for master, latest and stable

Could solve it by enabling the SemVer matcher: https://docs.readthedocs.io/en/stable/guides/automation-rules.html