Prefer default Debug and Release configs

[john-flanagan]

The default schemes generated for a target is using the suitableConfig helper function to prefer configs named "Debug" or "Release" over the alphabetically first scheme of the matching type:

XcodeGen/Sources/XcodeGenKit/SchemeGenerator.swift

Lines 57 to 58 in 480477a

	let debugConfig = suitableConfig(for: .debug, in: project)
	let releaseConfig = suitableConfig(for: .release, in: project)

but generateScheme(_: Scheme) was using the computed default<ConfigType>Config properties which only took into account the sorting order for top level schemes.

XcodeGen/Sources/XcodeGenKit/SchemeGenerator.swift

Lines 244 to 250 in 480477a

	let archiveAction = XCScheme.ArchiveAction(
	buildConfiguration: scheme.archive?.config ?? defaultReleaseConfig.name,
	revealArchiveInOrganizer: scheme.archive?.revealArchiveInOrganizer ?? true,
	customArchiveName: scheme.archive?.customArchiveName,
	preActions: scheme.archive?.preActions.map(getExecutionAction) ?? [],
	postActions: scheme.archive?.postActions.map(getExecutionAction) ?? []
	)

This change uses the same suitableConfig function to back the default<ConfigType>Config properties so that top level schemes and target schemes will have the same default config behavior.

[yonaskolb]

Great, thanks @john-flanagan! Could you please add a changelog entry as well