topic addition for better community reach

Hey,
for better reach of the community, I would like to suggest to add the following topic to the repository: `motorola-68000`

[How to do this](https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/classifying-your-repository-with-topics#adding-topics-to-your-repository)