Strongly type the `DependencyGroup.Rules` property.

[brettfo]

The current behavior is string-based and from analyzing the Ruby code, the expected values seem to be:

patterns => string array where each item is a wildcard match on a package name. Note, if empty, default to "*"
exclude-patterns => string array where each item is a wildcard match on a package name.
dependency-type => (production|development) determine if relevant for NuGet.