[MacPorts] #66852: cairo, cairo-devel: Update to 1.18.0

[MacPorts]

#66852: cairo, cairo-devel: Update to 1.18.0
--------------------------------+----------------------
  Reporter:  ryandesign         |      Owner:  mascguy
      Type:  update             |     Status:  assigned
  Priority:  Normal             |  Milestone:
 Component:  ports              |    Version:  2.8.1
Resolution:                     |   Keywords:
      Port:  cairo cairo-devel  |
--------------------------------+----------------------

Comment (by ryandesign):

 I wouldn't include demos in a tests variant (unless of course they are
 required to run the tests).

-- 
Ticket URL: <https://trac.macports.org/ticket/66852#comment:21>
MacPorts <https://www.macports.org/>
Ports system for macOS