unreported Homebrew failures
In addition to #2411 (closed), #2422 (closed), and #2423 (closed), the macOS M1 runners have developed an exciting behavior where Homebrew update steps fail and there is no discernible error message: https://gitlab.com/graphviz/graphviz/-/jobs/4570050094. AFAICT this blocks any work on #2411 (closed), #2422 (closed), #2423 (closed).