[MacPorts] #58395: drupal8: update to 8.6.15

[MacPorts]

#58395: drupal8: update to 8.6.15
--------------------------+---------------------
 Reporter:  chrstphrchvz  |      Owner:  (none)
     Type:  update        |     Status:  new
 Priority:  Normal        |  Milestone:
Component:  ports         |    Version:
 Keywords:                |       Port:  drupal8
--------------------------+---------------------
 `drupal8` is still at version 8.4.0, the same as when the port was added
 in 2017: [2b714ebf6e/macports-ports]. 8.4.x is unsupported and no longer
 receives security fixes. The latest available is 8.6.15.

 Updates for Drupal, especially security fixes, are rather frequent. I'm
 not sure there should be port(s) for Drupal if no one is willing to keep
 them up to date.

-- 
Ticket URL: <https://trac.macports.org/ticket/58395>
MacPorts <https://www.macports.org/>
Ports system for macOS