[MacPorts] #61093: port upgrade graphviz fails on 10.15

[MacPorts]

#61093: port upgrade graphviz fails on 10.15
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  Reporter:  breiter  |      Owner:  (none)
      Type:  defect   |     Status:  new
  Priority:  Normal   |  Milestone:
 Component:  ports    |    Version:
Resolution:           |   Keywords:
      Port:           |
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Comment (by mf2k):

 In the future, please fill in the Port field and add the port
 maintainer(s) to Cc ({{{port info --maintainers gnuradio}}}), if any.

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Ticket URL: <https://trac.macports.org/ticket/61093#comment:1>
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