Replace the deprecated `license_file` key with `license_files`.
The latter has the same semantics and is available since setuptools
42.0.0 (that lark already requires).

setup.cfg: Replace deprecated license_file with license_files

Fix Github shenanigans

Fix AmbiguousExpander (Issue #1214)

Generator is memory efficient approach.

Also improve performance of "iter_subtrees_topdown"
Performance of "iter_subtrees_topdown" method reduce as size of tree increases. Using instance of list method improve the performance.

Fix EOF line information in InteractiveParser.resume_parse()

Use generator instead of list expand or add method