Adjust for Swift 5.6

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Coverage after merging swift56 into main

74.09%

Coverage Report

File	Stmts	Funcs	Lines	Uncovered Lines
Sources/SwiftDependencyUpdaterLibrary
Dependency.swift	52.81%	60%	51.90%	46–64
PackageDescription.swift	74.34%	69.23%	75%	100–104, 121–123, 148, 165–172, 183–184, 45–47, 98–99
ResolvedPackage.swift	88.41%	100%	87.10%	117–118, 22–23, 84–85, 94–95
SwiftDependencyUpdater.swift	100%	100%	100%
SwiftPackage.swift	92.41%	83.33%	93.15%	56, 68–69, 74–75
SwiftPackageUpdate.swift	73.97%	100%	71.21%	40–41, 49–50, 53–54, 57–69
Update.swift	59.15%	75%	58.21%	29, 32, 35, 40–41, 43–65
Sources/SwiftDependencyUpdaterLibrary/Extensions
Collection.swift	100%	100%	100%
String.swift	100%	100%	100%
Version.swift	0%	0%	0%	11–17, 19–32, 36–43
Sources/SwiftDependencyUpdaterLibrary/Services
Git.swift	88%	83.33%	88.89%	62–64, 71–74
GitHub.swift	67.19%	80%	66.10%	60–61, 63–64, 67–79, 84–86
Sources/SwiftDependencyUpdaterLibrary/SubCommands
GitHubCommand.swift	82.61%	37.50%	86.90%	12–13, 45, 47–53
ListCommand.swift	78.38%	20%	87.50%	21, 24, 33
UpdateCommand.swift	65.96%	20%	71.43%	19, 21–27, 32–34