yetus-homebrew tests are failing

Error: You are using macOS 11.
We (and Apple) do not provide support for this old version.
It is expected behaviour that some formulae will fail to build in this old version.
It is expected behaviour that Homebrew will be buggy and slow.
Do not create any issues about this on Homebrew's GitHub repositories.
Do not create any issues even if you think this message is unrelated.
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Try to figure out the problem yourself and submit a fix as a pull request.
We will review it but may or may not accept it.