astro/opencpn: Update to 5.2.4

• New Plugin Management System
• Support for signalK input data streams
• New Head-Up Navigation Mode
• Docking the Dashboard with dual canvases
• Realtime prediction of AIS target location

Changelog: https://opencpn.org/OpenCPN/about/ver520.html

PR: 252168
Submitted by: Andrea Venturoli <ml@netfence.it> (maintainer)
Approved by: arrowd (mentor)
Differential Revision: https://reviews.freebsd.org/D27798