chore: update renovate-security-bump.sh with shfmt formatting

Syncs script with latest version from renovate-config that includes:
- shfmt formatting (2-space indents)
- pyproject.toml versioning support

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: lawrence-u10d