Reportportal-client

Added
- `CONTENT_TYPE_TO_EXTENSIONS` constant in `helpers` module, by HardNorth
Fixed
- Issue [228](https://github.com/reportportal/client-Python/issues/228): AttributeError on very large request, by HardNorth
Changed
- `helpers.gen_attributes` now accepts `Iterable[str]` argument instead of `List[str]`, by HardNorth

Added
- `is_binary` method in `helpers` module, by HardNorth
- `guess_content_type_from_bytes` method in `helpers` module, by HardNorth

Added
- Issue [225](https://github.com/reportportal/client-Python/issues/225): JSON decoding error logging, by HardNorth
Fixed
- Issue [226](https://github.com/reportportal/client-Python/issues/226): Logging batch flush on client close, by HardNorth

Fixed
- Python 3.7 support, by HardNorth
- Launch UUID attribute for AIO clients, by HardNorth
- Http timeout bypass for Sync Client, by HardNorth

Fixed
- Attribute truncation for every method with attributes, by HardNorth

Fixed
- Multipart file upload for Async clients, by HardNorth