Official GitHub Action

[lukehinds]

We have https://github.com/PyCQA/bandit-action

Shortly we will have an official image: #1088

Let's get the action work complete and publish to the marketplace.

cc: @JAORMX who I know is interested in working on this.

[ericwb]

You can now find an official action on the marketplace: https://github.com/marketplace/actions/bandit-by-pycqa