Use the same .swift-format in the repo and in the generated code

[czechboy0]

We use swift-format both for formatting the generator code, and the generated code. However, the configuration is duplicated in both places, we should have one source of truth for it instead.

[denil-ct]

I've opened a PR for this. Please have a look.

[czechboy0]

Well, this is good timing: swiftlang/swift-package-manager#6067

Unfortunately, it's only supported in Swift 5.9, so I propose we punt this issue until later, and adopt it when we bump the minimum tools version to 5.9.

[denil-ct]

Sounds good to me. So sometime in the fall when Xcode 15 comes out of beta I assume?

[czechboy0]

To be determined, but marking as blocked for now. You can close your other PR for now, but we'll definitely appreciate the contribution when Swift OpenAPI Generator requires Swift tools version 5.9!

[czechboy0]

Filed #75 to properly relate the two.