Avoid hard-coding the package version

[jhlegarreta]

Docker is being unable to identify the version for the tractolearn package:

LookupError: setuptools-scm was unable to detect version for /tractolearn.

The current workaround is to pretend a version for the package:
https://github.com/scil-vital/dockerfile_tractolearn/blob/main/Dockerfile#L6

Docker, through setuptools-scm, may be trying to do something like

import tractolearn
tractolearn.__version__

and it is failing because the property is not defined: it does not work either if you try in the console:

AttributeError: module 'tractolearn' has no attribute 'version'

For this to exist it must be defined in tractolearn.__init__: if I put __version__ = "0.0.1", the command tractolearn.__version__ works. So to do it automatically it would be necessary to put something like

import pkg_resources
__version__ = pkg_resources.require("tractolearn")[0].version

The next step would be to read the name "tractolearn" automatically:

1. From the pyproject.toml file, or
2. Using

   from setuptools_scm import get_version
   __version__ = get_version()
   

To do 1, tomli and the "pyproject.toml" file must be installed/locatable; to do 2. setuptools_scm must be installed.

The other option is to read the version from tractolearn/_version.py which is written at build time by setuptools_scm.

Slightly related to
scil-vital/tractolearn#37 (comment)
(Adopting a single way to read the version may ease maintenance)

Probably this is required regardless of Docker to be able towards building a PEP-compliant package:
https://peps.python.org/pep-0396/

[jhlegarreta]

Cross-referencing scil-vital/tractolearn#39.