Consider adding support for Git Updater and RepoMan

Hello there,

Please consider adding support for Git Updater and RepoMan by adding these lines to your plugin header:

```
GitHub Plugin URI: xwp/stream
Primary Branch: master
```

Ref: https://github.com/xwp/stream/blob/develop/stream.php

More info:

https://github.com/littlebizzy/repoman