Popper

New features in this release:

* Singularity actions are now fully supported (see [docs](https://popper.readthedocs.io/en/2.1.0/sections/extensions.htmlsingularity)).
* Workflows can reference actions hosted on arbitrary Git repositories (see [docs](https://popper.readthedocs.io/en/latest/sections/extensions.htmldownloading-actions-from-arbitrary-git-repositories)).
* Generate a `.dot` diagram of a workflow.
* Many codebase improvements such as the use of `docker-py` and `singularity-cli`, and misc. improvements.

We would like to immensely thank barbaraDorame, JayjeetAtGithub, akashrajr1 and arshul for all their contributions.

bug fix release

Popper 2.0 based on github actions.

Bug fix release

Release containing all features, fixes and documentation for summer 2018

Popper 1.0 is here! Main change is the move to Python from Go. This is also a backwards-incompatible version, any repos using previous versions of Popper need to be re-popperized. Highlights of this version include:

* Support for archiving to Zenodo (thanks to ankan17!)
* Initial search and import functionality (thanks to UjjwalAyyangar!)
* New examples of popper pipelines on the github.com/popperized org (thanks to eltrufas and franko1307!)
* Handling metadata for a paper as part of the `.popper.yml` file.
* Colorized output on the CLI (thanks to ankan17, UjjwalAyyangar, pcwilcox and shamedian!)
* Popper pipeline visualization improvements (thanks to UjjwalAyyangar!)