Add inital support for 3.12

[cooperlees]

• Move to version 6.6.0dev0
• Make CI pass for 3.12
  • Drop support for swift unless someone speaks up and wants to help support it - This will cause a temporary coverage reduction
  • Move python_requires + GitHub actions to >= 3.11 only
• Leave swift for one more release + document deprecating support due to no one to help maintain
• Fix remaining s3path 3.12 fun
  • Move to 3.12 private _generate_prefix until we workout correct way
  • Move last missed uses of private configuration_map

Test:

• Run /tmp/tb_312/bin/pre-commit run -a
• Run tox in py312
  • /tmp/tb_312/bin/tox