[MacPorts] #69924: opencv3: update to 3.4.20

[MacPorts]

#69924: opencv3: update to 3.4.20
-------------------------------------+----------------------
  Reporter:  mohd-akram              |      Owner:  mascguy
      Type:  update                  |     Status:  assigned
  Priority:  Normal                  |  Milestone:
 Component:  ports                   |    Version:
Resolution:                          |   Keywords:
      Port:  opencv3, opencv3-devel  |
-------------------------------------+----------------------
Description changed by mohd-akram:

Old description:

> https://github.com/opencv/opencv/wiki/ChangeLog#version3420

New description:

 https://github.com/opencv/opencv/wiki/OpenCV-Change-
 Logs-v2.2%E2%80%90v4.10#version3420

--

-- 
Ticket URL: <https://trac.macports.org/ticket/69924#comment:2>
MacPorts <https://www.macports.org/>
Ports system for macOS