Support type checking

[Spenhouet]

Python 3 support typing: https://docs.python.org/3/library/typing.html

For static type checkers like Mypy, PyRight, ... to properly work, packages need to support typing: https://mypy.readthedocs.io/en/latest/installed_packages.html

blosc currently does not provide stub files. Could type checking be supported in the future?

[FrancescAlted]

I agree that it would be nice. PR are welcome. It would probably be better to start with python-blosc2, which is the next generation of this package.