Poetry: post migration tasks (black, poetry)

• Add black as a dev dependency. Will be installed in case Python used is ≥ 3.6 in order to keep Py3.5 compatibly.
  • Update CONTRIBUTING.md.
• Add minimal Poetry version dependency: Specifying v1 does not prevent v0.12 to be installed.

changed milestone to %0.8.0

added Dev Env Install enhancement labels

assigned to @moul

changed the description

mentioned in commit b33f8fa3

marked the checklist item Add black as a dev dependency. Will be installed in case Python used is ≥ 3.6 in order to keep Py3.5 compatibly. as completed

closed

changed title from Poetry: post migration tasks to Poetry: post migration tasks (black, poetry)

mentioned in issue #286 (closed)

reopened

Reopened because black can only be installed with Python v3.6.

mentioned in commit 307a67ae

mentioned in merge request !127 (merged)

closed via merge request !127 (merged)

added Dep label