fix: correct version regex in semantic release config for version updates

[Bjarten]

Overview

This PR fixes an issue with python-semantic-release where the version in __init__.py was not updated during releases due to an incorrect version_variable configuration in pyproject.toml.

Changes Made

1. Updated version_variable in pyproject.toml:
   • Changed the version_variable setting to use an explicit regex pattern: early_stopping_pytorch/__init__.py:^__version__ = "(.*)".
   • This pattern directly matches the format of the version string in __init__.py, allowing python-semantic-release to locate and update it successfully.