Rudder-sdk-python

Fixes
- Fixed versions of dotenv dependency. Moved to use a higher upper limit (2.0.0)
- Updated License

Fixes
- Fixed versions of dependencies. Moved to use flexible depencencies.
- Updated License

Fixes
- Fixed dataPlaneUrl setter issue [20](https://github.com/rudderlabs/rudder-sdk-python/issues/20)

Fixes
- Default gzip value is set to True

Features
- Update SDK with latest code.
- Update tests with latest dependencies
Breaking Changes
- Updated package name to rudderstack.analytics
- Added optional gzip capabilities
- Batch size reduced to 500KB
- Max message size reduced to 32KB
- flush_at is now renamed to upload_size
- flush_interval renamed to upload_interval
- Removed support for python 3.6