[MacPorts] #42273: Support release downloads in GitHub portgroup

[MacPorts]

#42273: Support release downloads in GitHub portgroup
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  Reporter:  bgilbert@…   |      Owner:  macports-tickets@…
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.2.1
Resolution:               |   Keywords:  haspatch
      Port:               |
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Comment (by ryandesign@…):

 Thanks, that looks simple enough. I'll probably refactor the code a little
 before committing.

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Ticket URL: <https://trac.macports.org/ticket/42273#comment:2>
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