[MacPorts] #53937: upgrade claws-mail to 3.15.0

[MacPorts]

#53937: upgrade claws-mail to 3.15.0
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  Reporter:  pmetzger    |      Owner:
      Type:  update      |     Status:  new
  Priority:  Normal      |  Milestone:
 Component:  ports       |    Version:
Resolution:              |   Keywords:  haspatch maintainer
      Port:  claws-mail  |
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Changes (by pmetzger):

 * Attachment "claws-mail-Portfile.diff" added.

 diffs for Portfile

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Ticket URL: <https://trac.macports.org/ticket/53937>
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