Setup swift-format

[uhooi]

References

• https://github.com/apple/swift-format
• https://zenn.dev/kyome/articles/a2dad672c0a65c
• https://twitter.com/the_uhooi/status/1407199365693788163?s=20
• https://twitter.com/tokorom/status/1407192868612034564?s=20
• https://twitter.com/Kyomesuke/status/1411953672192331782?s=20

[github-actions[bot]]

👋 Thanks for reporting! Please PR :)