fix break for build prior to modernisation

Author: enetheru

cmake/godotcpp.cmake

@@ -293,4 +293,8 @@ function( godotcpp_generate )
 
  endforeach ()
 
+ # Added for backwards compatibility with prior cmake solution so that builds dont immediately break
+ # from a missing target.
+ add_library( godot::cpp ALIAS template_debug )
+
 endfunction()