Pybankid

What's Changed
* Merge changes into master. by hbldh in https://github.com/hbldh/pybankid/pull/64
* Broke out `generate_qr_code_content` from static method to a pure method (62)
* Fix for deprecated pytest usage (63)
* Markdown README instead of RestructuredText

**Full Changelog**: https://github.com/hbldh/pybankid/compare/v1.0.0...v1.0.1

Async and Sync clients, implementing v6 BankID API (59)

**Breaking changes**: Deprecating v5 of BankID API clients in favour of only v6 clients.

- Sync and Async clients
- Implementing the v6 API
- Removing all v5 and v5.1 API implementations
- Updated documentation
- Corrected the example app to work with v1.0.0 of PyBankID
- Contains and fixes 53, 54, 56, 57, 58

Big thanks to tiwilliam and mxamin for implementing the async client and v6 clients respectively.

- Updated test certificate and handling of it
- Read the docs config added

Fixes due to changes in `urllib3` and some issues with test certificate fetching.

Updated test certificate url

Merged PR 43 which solves 42 and 44.

Now uses the BankID API version 5.1 endpoint instead of 5.