Release 1.4.0

[bgilbert]

OpenSlide Python release process

• [x] Update CHANGELOG.md and version in openslide/_version.py
• [x] Create and push signed tag
• [x] Find the workflow run for the tag
  • [x] Once the build finishes, approve deployment to PyPI
  • [x] Download the docs artifact
• [x] Verify that the workflow created a PyPI release with a description, source tarball, and wheels
• [x] Verify that the workflow created a GitHub release with release notes, a source tarball, and wheels
• [x] cd into website checkout; rm -r api/python && unzip /path/to/downloaded/openslide-python-docs.zip && mv openslide-python-docs-* api/python
• [x] Update website: _data/releases.yaml, _includes/news.md
• [ ] Start a CI build of the demo site
• [ ] Update Ubuntu PPA
• [x] Update Fedora ~and EPEL~ packages
• [ ] Check that Copr package built successfully
• [ ] Send mail to -announce and -users
• [ ] Post to forum.image.sc
• [x] Update MacPorts package

[bgilbert]

Automatic creation of the GitHub release failed due to #301, so I've created the release manually from the GitHub Actions run artifacts.

[bgilbert]

Skipping EPEL update because the changes relevant to EPEL aren't worth the churn per the EPEL update policy.

[bgilbert]

It's no longer feasible to keep the EPEL 8 package building on the system Python, which is 3.6 and thus unsupported. The EPEL 8 Copr will stay at OpenSlide Python 1.3.1.

[bgilbert]

Distro packages on older distros need #306. Closing in favor of #307.