Fix a typo in macos.md [skip ci]
Fix a typo in macos.md [skip ci]


Former-commit-id: 6959120d8033255956e6fa8394eddf4fd99e1e53 [formerly a74c6e64d3086e9aefe9adfeb2879e289efd21de] [formerly a74c6e64d3086e9aefe9adfeb2879e289efd21de [formerly 137b3bd3bafe429dcd5bad82bd782e2064d5a955]]
Former-commit-id: b59e9cdf233a3691bb7600d7221487b9855ca5a7
Former-commit-id: a8f448a22db75f9428b2b6c702e0caa59f36d799
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine