Add new github actions

## Motivation
This issue summarizes the github actions that we plan to introduce in the future. Please feel free to leave comments.

## TODOs
- [x] [flake8](https://github.com/PyCQA/flake8) (or [hacking](https://github.com/openstack/hacking))
  - https://github.com/st-tech/zr-obp/pull/84 
- [ ] [mypy](https://github.com/python/mypy)
- [ ] [isort](https://github.com/PyCQA/isort)