[MacPorts] #57259: py-isodate: add py37 subport

[MacPorts]

#57259: py-isodate: add py37 subport
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  Reporter:  petrrr       |      Owner:  esafak
      Type:  enhancement  |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:
      Port:  py-isodate   |
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Comment (by esafak):

 Go for it.

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Ticket URL: <https://trac.macports.org/ticket/57259#comment:1>
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