Big changes in release 0.28.0

[cgrindel]

@brentleyjones contribution #883 has a couple of important changes:

• Swift package manager products are now represented by a single swift_library_group Bazel target. Previously, a product was represented by one or more Bazel targets.
• The Bazel targets generated for Swift packages are much shorter. Previously, the Bazel target labels were derived from an SPM target's path and name. Now, Bazel targets for SPM targets are <target name>.rspm and for SPM products is <product name>.

When you upgrade to this release, be sure to run //:swift_update_pkgs and //:update_build_files. If you do not use the Gazelle plugin to manage your build files, you will need to manually update the Swift package dependencies in your project.

If you have any questions or run into any issues, please open an issue.