Version check: count the CI workflow as build #42

.github/check-version.sh requires a new version for src/, the installers, the Makefile and ci/, but not for .github/workflows/ci.yml. A workflow edit that changes the build itself (compiler flags, an image, a build step) changes the release files without a new version.

Proposal: count ci.yml as build. A workflow edit that leaves the binaries as they are (tests, Telegram, publication) takes the existing no-release label (#39). CI only: no version bump.