update to gd v4.2

[jinsediaoying]

in plugin.gd file, line 15
change
var godot_theme = get_editor_interface().get_base_control().theme
to
var godot_theme = get_editor_interface().get_editor_theme()

[YuriSizov]

Done in c4a3d5e. Version 2.1.0 is compatible with Godot 4.2, soon to be available on the asset lib.