Added the restriction to instantiate the apysc data types (v3.2.1)

[simon-ritchie]

Since version 3.2.1, the apysc data types, such as the ap.Int, ap.Number, ap.String,ap.Boolean, ap.Array, and ap.Dictionary, cannot be instantiated before an ap.Stage creation.

For example, the following code raises an exception:

import apysc as ap

my_int: ap.Int = ap.Int(10)
ap.Stage(
    stage_width=100, stage_height=50, background_color="#333", stage_elem_id="stage"
)

If you encountered that exception, please instantiate a data class (such as the my_int: ap.Int = ap.Int(10)) after a stage creation:

import apysc as ap

ap.Stage(
    stage_width=100, stage_height=50, background_color="#333", stage_elem_id="stage"
)
my_int: ap.Int = ap.Int(10)