Streamparse

Features
* Raise an exception when `run_cmd` does not return an exit code of 0. (PR 492)

Features
* Switch to using [`Fabric39`](https://github.com/parsely/fabric) for Python 3.9.X compatibility (PR #490)
* Upgrade `setuptools` during virtual environment creation for Python 3.9.X compatibility (PR 489)

⚠️ Backward Incompatible Changes ⚠️
- streamparse now only supports Python 3.6+

Features
- Switched depending on `thriftpy` to `thriftpy2`, because `thriftpy` is no longer maintained (PR 481)

Features
- Faster virtualenv creation when passing multiple requirements files to `sparse submit` (PR 459)
- Add `sudo_user` option to `config.json` that can be used for specifying a different user that is used for virtualenv creation/deletion instead of always using the SSH login user. (PR 455)

Fixes
- Fix typo that would cause `update_virtualenv` to when no CLI options were passed (PR 459)

⚠️ In the upcoming streamparse 4.0 release, support for Python 2 will be dropped. ⚠️

Fixes
- Make `update_virtualenv` create virtualenvs as sudo user, and not just when trying to delete them (0250cfa)
- Prevent pip 19.0 from being installed because it breaks `--no-cache-dir` installs (db26183)
- Prevent virtualenv from downloading pip versions other than what we have pinned (0573bc8)
- Make redis examples work with `sparse run` again (b61c85d)
- Fix issues where `repr(Topology)` was always `None` (fd5b4b6)

Misc.
- Simplify Travis setup (454)

Features
- Allow submitting topologies as inactive/deactivated (PR 448)
- Stop pinning pip to 9.x when running `update_virtualenv` (PR 444)

Fixes
- Added missing `options` argument to bootstrap project (PR 436)
- Import fixes in redis example (PR 451)
- Fix issues with virtualenv-related option resolution, which made options only in `config.json` not get used. (PR 453)

Misc.
- Reformatted code with [black](https://black.readthedocs.io/en/stable/)