* Add downgrade command
* Add docs per @lexi-lambda's suggestions
* make tests pass
* Update hdb_version once, from Haskell
* more work based on feedback
* Improve the usage message
* Small docs changes
* Test downgrades exist for each tag
* Update downgrading.rst
* Use git-log to find tags which are ancestors of the current commit
Co-authored-by: Vamshi Surabhi <0x777@users.noreply.github.com>
