Switch DuniterPy usage back to PyPI release
DuniterPy is currently used from `git` `main` branch.
Once DuniterPy v1.2.0 is released:
- [x] Switch DuniterPy back to stable release from PyPI (`~1.2.0`)
- `~` allows patches updates
- [x] Switch DeathReaper repo back to `pip` image (#443) (lightweight image)
- I don’t think DuniterPy will be used from `git` again, otherwise following change can be re-introduced
- Revert 6d846c77
issue