Change version import to relative import

[eddyxu]

No description provided.

[eddyxu]

Failed during building docs

Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/lance-docs/envs/lei-docs/lib/python3.10/site-packages/sphinx/ext/autodoc/importer.py", line 58, in import_module
    return importlib.import_module(modname)
  File "/home/docs/.asdf/installs/python/3.10.4/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/home/docs/checkouts/readthedocs.org/user_builds/lance-docs/checkouts/lei-docs/lance/python/lance/__init__.py", line 25, in <module>
    __version__ = lance.version.__version__
AttributeError: partially initialized module 'lance' has no attribute 'version' (most likely due to a circular import)