154 pietro integrates some best practices within cobra

[pietrodantuono]

Integration of git-changelog package and invoke command for easier development

Pietro integrates some best practices within Cobra #154

Additions made

Added some automated development tasks through the invoke command. To test it:

• install the dev and notebook dependencies in your virtual environment
• run one of these invoke tasks (works on Linux, macOS, Windows):
• inv test, inv qa, inv nb.

Added git-changelog package dependency to simplify change log generation (https://pawamoy.github.io/git-changelog/).

How does the solution address the problem

This PR will:

• simplify testing development by offering automated coverage
• simplify quality assessment by offering customisable linting, type-hinting, and possibly formatting (black).
• simplify cobra development via inv nb that automatically creates a jupyter environment in developer mode, i.e. every change in the cobra source code will be reflected immediately in the jupyter kernel.
• simplify the change log generation via the git-changelog command which will be in the near future added as an invoke command.

Linked issues

Resolves #154