Release v0.6.4

This updates the copier workflow to make it more user-friendly. It also removes some extra items from the "minimal version" of the package.

What's Changed

• rename use_default to template_mode in file/dir level template strings by @sneakers-the-rat in #103
• reorder minimal questions, make email optional by @sneakers-the-rat in #107
• Cleanup: readme file and a few more extra files that we don't need for "minimal mode" by @lwasser in #105
• enh: cleanup and organization pyproject.toml by @lwasser in #109

Full Changelog: v0.6.3...v0.6.4