Owlkettle 2.0.0 is a declarative GUI framwork for GTK 4

[elcritch]

Also I really am enjoying the feel of using the `=` instead of a more YAML like 
`:` pattern I'm using for attributes in Fidgetty. It just feels slightly more 
"open". Maybe I'll switch to that DSL call style. :-)
    
    
    Button {.expand: false.}:
              text = "+"
              style = {ButtonSuggested}
              proc clicked() =
                app.counter += 1
    
    
    Run

vs the more YAML-like DSL style:
    
    
    Button(expand = false):
              text: "+"
              style: {ButtonSuggested}
              onClick:
                app.counter += 1
    
    
    Run