Update gtk-rs deps
The latest gtk-rs release comes with a very useful macro for creating closures. These macros can infer the types of arguments and handle giving us the correct type. This means we don't need to manually cast GValues.
The latest gtk-rs release comes with a very useful macro for creating closures. These macros can infer the types of arguments and handle giving us the correct type. This means we don't need to manually cast GValues.