With continue-on-error set so failures don't break the build

Co-authored-by: Oscar Gustafsson <[email protected]>

To deep copy an object without calling deepcopy on the object itself,
create a new object of the correct class and iterate calling deepcopy on
its __dict__.

Closes matplotlib#29157 without relying on private CPython methods.
Does not fix the other issue with TransformNode.__copy__.

Co-authored-by: Serhiy Storchaka <[email protected]>

Co-authored-by: Elliott Sales de Andrade <[email protected]>

without calling copy.copy

…314-checks

And tweak some dependencies