It causes lots of pain when building with `nix` for a local `flake.nix`.
Not sure if it's a good general solution:
* now it requires a manual step of updating `./version` on each release.
* we're losing commit hash abbreviation, like `0.5.3-5-gbe5a291`
I guess, this can be fixed by installing git-pre-commit-hook, but even
then it'd be wrong, because the output of `git describe --tags --always`
won't be the same before and after commit.
