Starknet.py

What's Changed
* ⚠️ **Change package name to `starknet_py`**
* Add contributing guide
* Add uint256 to docs
* Implement felt range checking
* Shortstring support


**Full Changelog**: https://github.com/software-mansion/starknet.py/compare/0.1.2-alpha...0.1.3-alpha

What's Changed
* Add errors by Solpatium in https://github.com/software-mansion/starknet.py/pull/53
* Add cairo 0.6.2 by Solpatium in https://github.com/software-mansion/starknet.py/pull/54


**Full Changelog**: https://github.com/software-mansion/starknet.py/compare/0.1.1-alpha...0.1.2-alpha

What's Changed

* Exclude tests from package (0.1.1-alpha) by Arcticae in https://github.com/software-mansion/starknet.py/pull/51


**Full Changelog**: https://github.com/software-mansion/starknet.py/compare/0.1.0-alpha...0.1.1-alpha