The empty homebrew tap was never a condition problem. The release job ran, the
matrix built all six targets, and the tap step then failed with "Input required
and not supplied: token" because HOMEBREW_TAP_TOKEN resolves to an empty
string. Four rounds of edits to those `if` expressions chased a symptom, so
they go back to what they were.
What stays is the CI concurrency change: a cancelled master run leaves the
release gate waiting on a CI run for a commit nothing will push again.
Michel de Graaf
c27f2b8467