Rollbar-agent

- Fix PyPI artifacts

- Add Python3 support. See [60](https://github.com/rollbar/rollbar-agent/pull/60)
- Add config option `state_proto`. See [60](https://github.com/rollbar/rollbar-agent/pull/60)
- Remove support for building snap packages. See [57](https://github.com/rollbar/rollbar-agent/issues/57)

- Improve error handling: See [50](https://github.com/rollbar/rollbar-agent/pull/50)

- add content-type: application/json to post request [39](https://github.com/rollbar/rollbar-agent/pull/39)
- Support multiple spaces in in log_format.patterns [38](https://github.com/rollbar/rollbar-agent/pull/38)
- Add option to filter character attribute modifying terminal escape sequences [36](https://github.com/rollbar/rollbar-agent/pull/36)

- Improve internal error handling. See [35](https://github.com/rollbar/rollbar-agent/pull/35)

- Fix a few installation issues, and bump minor version.