Use Xcode 16.0 for GitHub Action test

[S-Shimotori]

Closes #3

Changes

This PR will

• make GitHub Action use Xcode 16.0.
• give a name to each step.
• insert -skipPackagePluginValidation option to skip SwiftLintBuildToolPlugin validation

https://github.com/S-Shimotori/SampleViewer/actions/runs/11320108808/job/31477139676

Validate plug-in “SwiftLintBuildToolPlugin” in package “swiftlint”
error: “SwiftLintBuildToolPlugin” must be enabled before it can be used