[MacPorts] #43785: merge zmq ports, remove zmq20

[MacPorts]

#43785: merge zmq ports, remove zmq20
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  Reporter:  michaelld@…                   |      Owner:  merijn@…
      Type:  enhancement                   |     Status:  new
  Priority:  Normal                        |  Milestone:
 Component:  ports                         |    Version:  2.2.1
Resolution:                                |   Keywords:
      Port:  zmq, zmq20, zmq22, zmq-devel  |
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Comment (by sean@…):

 I am definitely in favor of this. Thanks for the work!

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Ticket URL: <https://trac.macports.org/ticket/43785#comment:1>
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