Release patch release v0.20.3 with API breaking changes reverted

[matthewfeickert]

As outlined in #116 (comment), to deal with the fact that PR #92 introduced an API breaking change into patch release v0.20.2 we should

• Make branch v0.20.x in yadage where we revert PR coerce dataarg #92 so there isn't an API breaking change in it. This branch is a release branch for v0.20.X bug fixes into the future.
  • c.f. https://github.com/yadage/yadage/tree/v0.20.x
• Ensure the test suite is passing on branch v0.20.x
• Make yadage release v0.20.3 off of branch v0.20.x so that we can get the visualization fixes.
• Test v0.20.3 against recast-atlas and reana-workflow-engine-yadage and once that is working we make a PR that is the equivalent of setup: Set compatible releases for 'yadage' extra to be support 'yadage[viz]' reanahub/reana-commons#333.

[matthewfeickert]

Ensure the test suite is passing on branch v0.20.x

Hm, even after revering PR #92 the test suite is currently failing in quite a few places. This is strange as PR #92 passed its test suite (was on Travis CI here). The test suite is passing on master though, so this is confusing.

I'm attaching the diff that I get from

git diff origin/master

and from

git diff ff4239e b03a637

which should be inverses of each other basically.

• diff_reverted_branch_vs_master_at_314078e.txt
• diff_of_PR92_ff4239e_vs_b03a637.txt