Onelogin-aws-assume-role

* [10](https://github.com/onelogin/onelogin-python-aws-assume-role/issues/10) Be able to provide ip_address parameter to bypass MFA
* [7](https://github.com/onelogin/onelogin-python-aws-assume-role/issues/7) Fix Credential writer.
* Improve error handler: Detect when OL API Key data is wrong on initialization and detect when get_saml_assertion returns 400 or 401 and try to get new input when possible.
* Update dependencies: OneLogin Python SDK and Boto3

changelog:
* Avoid the use of .text directly to get node value. Instead remove comments before.
* Add ability to specify AWS region via argument too
* Select MFA device automatically if there is only one
* Add ability to specify username, app ID and subdomain via command-line
* Fixed issue with string concatenation because of int