release.md

OpenSlide release process

• Update CHANGELOG.md and version and soversion in meson.build
• Create and push signed tag
• Ensure Meson version is at least 0.60
• git clean -dxf && meson setup builddir && meson dist -C builddir
• Attach release notes to GitHub release and upload tarball
• Update openslide-winbuild
• Update website: _data/releases.yaml, _includes/news.md, api/
• Start a CI build of the demo site
• Update Ubuntu PPA
• Send mail to -announce and -users
• Update Fedora and EPEL packages
• Update MacPorts package