v63.0.0b1

This is a beta release including PEP 660 functionality.

Summary

• Implement PEP 660 allowing both "strict" and "lax/loose" approaches, #3265
• Handle config_settings as they would be passed by pip, #3380
• Update strict editable install to use get_output_mapping for the construction of the link tree, #3409, #3392
• Automatically add files from build subcommands (get_source_files) to sdist, #3412
• Improve docs and behavior of editable installs, #3414

Full Diff: v62.6.0...v63.0.0b1