[MacPorts] #60082: Fish @3.02 upgrade to 3.1

[MacPorts]

#60082: Fish @3.02 upgrade to 3.1
---------------------+--------------------
 Reporter:  akierig  |      Owner:  (none)
     Type:  update   |     Status:  new
 Priority:  Normal   |  Milestone:
Component:  ports    |    Version:  2.6.2
 Keywords:           |       Port:  fish
---------------------+--------------------
 `fish` 3.1.0 has been [https://github.com/fish-shell/fish-
 shell/releases/tag/3.1.0 released]. Unfortunately, my local revision of
 the portfile fails to build so I'm attaching it here instead of submitting
 through GH. If someone can tell me what I'm doing wrong, I'd be happy to
 put it through GH to update it.

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Ticket URL: <https://trac.macports.org/ticket/60082>
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