GitHub actions, pre-commit hooks, pyproject.toml and more

[Takishima]

Summary of changes

• Add support for GitHub actions (in replacement of Travis CI)
• Add configuration file for dependabot
• Add support for pre-commit Git hooks
• Use setuptools-scm for automatic versioning based on GitHub tags
• Add setup.cfg configuration file and move package metadata from setup.py
• Add pyproject.toml configuration file
• Add .editorconfig file
• Add CHANGELOG.md file

README for the reviewer

Since this is a PR with a quite large change-set, you can probably best review this PR in chunks (below are commit ranges):

• First 6 commits (da29a79..50a574f): most of the fundamental changes brought by this PR are located here
• Last 7 commits (d3ba306..df805dd): this is where the rest of the fundamental changes are
• Rest of the commits (752d633..ed063bb): changes to address the issues due to the new building and testing by the GitHub CI (ie. quasi no changes in functionality for ProjectQ just taking care of warnings from flake8, etc.)

GitHub Actions

Add support for GitHub actions (in replacement of Travis CI) for testing, linting and building binaries. ProjectQ now has 3 distinct pipelines:

• CI : dedicated to testing the building and installation of ProjectQ on multiple systems and compilers
• Format: run a series of pre-commit hooks, static analysis and linting tools such as pylint, flake8, clang-tidy, etc.
• PR: execute a few checks on each PR. For now mostly make sure that the PR modifies the CHANGELOG.md file.
• Draft release: Draft a new release on GitHub (create release branch, create PR, update changelog, etc.)
• Publish release: Create a new release on GitHub, build binary wheels, upload the wheels to GitHub and PyPi

Caveat

The move to GitHub Action and some of the others mentioned above means that this will most likely break the installation of ProjectQ with Python 3.5 or lower (and definitely break compatibility with Python 2.x). Compatibility with Python 3.5.x is still probably possible by lightly editing some configuration file (e.g. probably remove any mention of setuptools-scm in setup.py and pyproject.toml for regaining Python 3.5 compatibility).

Support pre-commit Git hooks

Added .pre-commit-config.yaml YAML configuration file for pre-commit to allow an easier time running a set of pre-commit hooks such as:

• A few of GitHub's pre-commit hooks
• check-manifest
• remove-tabs
• black
• flake8
• pylint

[andreashehn]

Looks good overall. I've got some questions and change requests fixing formatting.

[Takishima]

Thanks for the review! I have made the required changes in the code and marked those conversations as "resolved". For your questions, I will let you mark them as resolved once you are satisfied with my answers ;-)

[Takishima]

Ok, I think I have not managed to fix everything that was broken (somehow the CI builds that worked previously for Clang and GCC started to fail?!) and address the bug in the classical simulator.

If you're happy with those changes, then I will merge this in the coming days. Thanks again for your contribution and doing this review.

[Takishima]

Thanks a lot for you review @andreashehn !