get __version__ from package metadata

_version.py

+# coding: utf-8
+# file generated by setuptools_scm
+# don't change, don't track in version control
+version = '0.0.2.dev0+gb93bf20.d20220303'
+version_tuple = (0, 0, 2, 'dev0', 'gb93bf20.d20220303')

src/icartt/__init__.py

 from .dataset import Dataset, StandardNormalComments, Variable, Formats, VariableType
 
-# TODO: add __version__ ?
 
-# TODO: add __all__ = ("names of exported classes etc.",) ?
\ No newline at end of file
+def get_version():
+    try:
+        # Python >= 3.8
+        from importlib import metadata
+
+        return metadata.version("icartt")
+    except ImportError:
+        # Python <= 3.7
+        import pkg_resources
+
+        return pkg_resources.get_distribution("icartt").version
+
+
+__version__ = get_version()
+
+
+# TODO: add __all__ = ("names of exported classes etc.",) ?