build varies from date again

[bmwiedemann]

The build of osdlyrics in openSUSE had been reproducible since #34 but that changed with
b962861

One simple fix would be to add -r README.md now. Or redesign how that fallback works. See the discussion in #34 on possible approaches.

[PedroHLC]

Maybe we could change OL_BUILD_VER to 0 unless defined by the user? Or just start using git describe --always --tags --dirty=+ in OL_VERSION with no intermediaries (and a single hardcoded fallback).

[bmwiedemann]

git describe does not work in our distribution build, when we just have a release tarball.
Or you add some logic in the release workflow to add the data to the tarball and use it in there.

[PedroHLC]

I'm working in a change in https://github.com/osdlyrics/osdlyrics/tree/configure-version-git where having a .git directory + git in PATH, will lead to git describe being used, otherwise, the hard-coded version.