CI Lint fixes:
- docs/openapi.yaml: bump version 2.2.0 → 2.2.3 (was out of sync with package.json)
- CHANGELOG.md: add '## [Unreleased]' as first section (required by check:docs-sync)
Electron Linux fix:
- electron-release.yml: add 'gem install fpm' step for Linux builds
fpm is required by electron-builder to package .deb installers;
ubuntu-latest runners don't have it pre-installed
Docker publish:
- docker-publish.yml: add DOCKER_BUILDKIT_INLINE_CACHE env; prev 502 was
a transient Docker Hub network error, no code change needed
diegosouzapw
6d672ab09a