clustermq 0.9.1

• Disconnect monitor (libzmq with -DZMQ_BUILD_DRAFT_API=1) is now optional (#317)
• Fix a bug where worker shutdown notifications can cause a crash (#306, #308, #310)
• Fix a bug where template values were not filled correctly (#309)
• Fix a bug where using Rf_error lead to improper cleanup of resources (#311)
• Fix a bug where maximum worker timeout was multiplied and led to undefined behavior
• Fix a bug where ZeroMQ's -Werror flag led to compilation issues on M1 Mac
• Fix a bug where SSH tests could error with timeout on high load
• Worker API: CMQMaster now needs to know add_pending_workers(n)
• Worker API: status report info() now displays properly