fix: Remove deprecated set-output command from version bump script

Removed deprecated ::set-output command that caused GitHub Actions to fail
during automated version bumping. The workflow failed trying to create
tag v4.0.8 instead of v4.0.9 because the deprecated command interfered
with proper version output capture.

The workflow already uses the correct modern method:
NEW_VERSION=$(python -c "from config import __version__; print(__version__)")
echo "version=$NEW_VERSION" >> $GITHUB_OUTPUT

This fixes the auto-version workflow failure from PR #13.

scripts/bump_version.py

@@ -104,7 +104,6 @@ def main():
 
         # Output new version for GitHub Actions
         print(f"New version: {new_version}")
-        print(f"::set-output name=version::{new_version}")
 
     except Exception as e:
         print(f"Error: {e}")