feat!: remove osx & windows platform

[erisu]

Platforms affected

osx, windows

Motivation and Context

Remove OSX and Windows platform.

Description

Since it was deprecated, this prepares the removal.

Testing

• n/a

Checklist

• [ ] I've run the tests to see all new and existing tests pass
• [ ] I added automated test coverage as appropriate for this change
• [ ] Commit is prefixed with (platform) if this change only applies to one platform (e.g. (android))
• [ ] If this Pull Request resolves an issue, I linked to the issue in the text above (and used the correct keyword to close issues using keywords)
• [x] I've updated the documentation if necessary
  • was already deprecated.