Update Tree Example

[usmcamp0811]

The Tree demo is broken. I tried following the deprication messages but I'm still running into problems.

╭─mcamp on Butler in ~/code/StippleDemos/BasicExamples/Tree on master🔥
╰─🚧 julia Tree.jl        
┌ Warning: @reactive! is deprecated, please replace use `@vars` instead.
│ 
│ In case of errors, please replace `@reactive!` by `@old_reactive!` and open an issue at
│ https://github.com/GenieFramework/Stipple.jl.
│ 
│ If you use `@old_reactive!`, make sure to call `accessmode_from_pattern!()`, because the internals for
│ accessmode have changed, e.g.
│ ```
│ model = init(MyDashboard) |> accessmode_from_pattern! |> handlers |> ui |> html
│ ```
└ @ Main ~/.config/julia/packages/Stipple/qnyBY/src/stipple/reactivity.jl:430
ERROR: LoadError: UndefVarError: register_mixin not defined
Stacktrace:
 [1] top-level scope
   @ ~/code/StippleDemos/BasicExamples/Tree/Tree.jl:39
in expression starting at /home/mcamp/code/StippleDemos/BasicExamples/Tree/Tree.jl:39
╭─mcamp on Butler in ~/code/StippleDemos/BasicExamples/Tree on master🔥
╰─🚧 vim Tree.jl        
╭─mcamp on Butler in ~/code/StippleDemos/BasicExamples/Tree on master🔥
╰─🚧 vim Tree.jl
╭─mcamp on Butler in ~/code/StippleDemos/BasicExamples/Tree on master🔥
╰─🚧 julia Tree.jl
ERROR: LoadError: type Bool has no field args
Stacktrace:
 [1] getproperty(x::Bool, f::Symbol)
   @ Base ./Base.jl:38
 [2] var"@var_storage"(__source__::LineNumberNode, __module__::Module, expr::Any, new_inputmode::Any)
   @ Stipple ~/.config/julia/packages/Stipple/qnyBY/src/stipple/reactivity.jl:258
 [3] var"@var_storage"(__source__::LineNumberNode, __module__::Module, expr::Any)
   @ Stipple ~/.config/julia/packages/Stipple/qnyBY/src/stipple/reactivity.jl:247
 [4] eval(m::Module, e::Any)
   @ Core ./boot.jl:368
 [5] var"@vars"(__source__::LineNumberNode, __module__::Module, expr::Any)
   @ Stipple.ReactiveTools ~/.config/julia/packages/Stipple/qnyBY/src/ReactiveTools.jl:151
in expression starting at /home/mcamp/.config/julia/packages/Stipple/qnyBY/src/ReactiveTools.jl:151
in expression starting at /home/mcamp/code/StippleDemos/BasicExamples/Tree/Tree.jl:27
in expression starting at /home/mcamp/code/StippleDemos/BasicExamples/Tree/Tree.jl:27

[AbhimanyuAryan]

hmm I see you are trying from old demos. We have moved to new Demos here but they are limited atm: https://github.com/GenieFramework/GenieFrameworkDemos_NewAPI

I'll try to update the docs directly(docstring) for StippleUI instead of updating the old demos. But can't promise a timeline atm. @PGimenez what are your thoughts on this?

[PGimenez]

hmm I see you are trying from old demos. We have moved to new Demos here but they are limited atm: https://github.com/GenieFramework/GenieFrameworkDemos_NewAPI

I'll try to update the docs directly(docstring) for StippleUI instead of updating the old demos. But can't promise a timeline atm. @PGimenez what are your thoughts on this?

We should add a deprecation notice to this repo's readme and slowly port the demos to the new API

[AbhimanyuAryan]

makes sense