CI/CD enhancements

[mloning]

A few useful change to improve our release/distribution cycle:

• compile manylinux wheels (see Compile manylinux wheels #188)
• set up CI to directly upload wheels to PyPI
• include Makefile to automise release workflow (see this intro, also see e.g. https://github.com/alan-turing-institute/CleverCSV/blob/master/make_release.py)
• enforce code formatting in released code (see Black formatting #208, Enforce linting #256)
• add coverage for unit tests (see Update CI and maintenance tools #394)
• add code quality/climate checks (see https://lgtm.com, https://www.codacy.com, https://github.com/marketplace/code-climate, etc)
• consider cibuildwheel package to simplify wheel building across platforms
• improve packaging for macOS wheels with delocate, also included in cibuildwheel, also see https://iscinumpy.gitlab.io/post/azure-devops-python-wheels/
• distribute sktime via conda-forge: https://conda-forge.org/#contribute (see Conda-Forge recipe request #326)
• set up pre-commit config (see Update CI and maintenance tools #394)
• add Black for code formatting (see Update CI and maintenance tools #394)
• add check-manifest (see Update CI and maintenance tools #394)
• add bugbear to flake8 (see Update CI and maintenance tools #394)
• update setup.cfg, see e.g. https://github.com/scikit-hep/boost-histogram/blob/develop/setup.cfg (see Update CI and maintenance tools #394)
• check out other flake8 extensions
• add checks for broken website links: https://fastpages.fast.ai/fastlinkcheck/
• use GitHub Action to check if Binder works and pre-build Docker images for quicker launch: https://github.com/jupyterhub/repo2docker-action#use-github-actions-to-cache-the-build-for-binderhub
• explore pre-commit-ci as suggested in Upgrade nbqa #794

Extra resources

• For building/distribution on GitHub Actions checkout: https://scikit-hep.org/developer/gha_wheels
• Useful links from reproducible research lunch
• scikit-learn's release process
• Check out https://python-poetry.org thanks to @hiqbal2
• Consider setuptools_scm for versioning (software configuration management)

[xuyxu]

Hi @mloning, I would like to work on using cibuildwheel to simplify the workflow on package building. You can check our package that uses cibuildwheel, it is quite convenient, and we can even build wheels for architectures like aarch64.

I have checked all supported python versions and platforms of sktime on PyPI, all of them can be built with cibuildwheel.

EDIT: Another benefit is that we can have sktime listed on the homepage of cibuildwheel as a way of advertisement ;-).

[mloning]

@xuyxu sounds good, one issue may be support for older macOS versions (see #748)

[TonyBagnall]

hi @mloning Im doing a tidy up, 200+ issues triggers me. Can this be closed?

[mloning]

Yes, turned it into a discussion now.

[fkiraly]

@freddyaboulton, @lmmentel, have you seen this?

[lmmentel]

Yes, I've seen it. Most of the concrete items are already implemented but in case someone feels that something is missing in CI it would be best to turn it into a specific issue so we can start working on it.