Added support for tvOS and watchOS

[bdunay3]

Description

This PR just adds support to use VSM on tvOS and watchOS. It also bumps the version of TestableCombinePublisher it that package also needed those platforms to be added in order to run VSM's unit tests on the new platforms.

Type of Change

• [ ] Bug Fix
• [x] New Feature
• [ ] Breaking Change
• [ ] Refactor
• [ ] Documentation
• [ ] Other (please describe)

Checklist

• [x] I have read the contributing guidelines
• [x] Existing issues have been referenced (where applicable)
• [x] I have verified this change is not present in other open pull requests
• [x] Functionality is documented
• [x] All code style checks pass
• [x] New code contribution is covered by automated tests
• [x] All new and existing tests pass