As the number of crates in the repo has grown, it has become a bit more tedious to ensure that all of the package fields are consistent and correct. This update just adds a simple test crate that validates some of the most important package manifest settings for consistency and correctness. Notably, it checks the following:

• There should not be an authors field as that is deprecated
• The edition should be 2021
• The license should be "MIT OR Apache-2.0"
• The repository should be "https://github.com/microsoft/windows-rs"
• The readme should be "readme.md" as Cargo assumes "README.md"
• The categories should be "os::windows-apis"
• There should be a non-empty description.
• Unpublished crates (samples/tests/tools) should omit most fields including version, license, repository, readme, categories, and description