Infra: remove unneeded swiftLanguageVersions param

[topkim993]

Replace deprecated 'swiftLanguageVersions' with 'swiftLanguageModes'

https://developer.apple.com/documentation/packagedescription/package/swiftlanguageversions

[zunda-pixel]

Hi @topkim993
if set // swift-tools-version:6.0 in Package.swift, We don't need to set swiftLanguageModes(.v6).
I think those effects is same.

[topkim993]

Hi, @zunda-pixel thanks for the feedback!
I’ve reflected the change by removing the explicit swiftLanguageModes(.v6) since setting // swift-tools-version:6.0 already implies Swift 6 mode.

• e5dfcdc

For reference, I followed the official Swift 6 migration guide here

• https://www.swift.org/migration/documentation/swift-6-concurrency-migration-guide/swift6mode