[MacPorts] #71748: boost PG: update default version to 1.87

[MacPorts]

#71748: boost PG: update default version to 1.87
------------------------+--------------------
 Reporter:  mohd-akram  |      Owner:  (none)
     Type:  update      |     Status:  new
 Priority:  Normal      |  Milestone:
Component:  ports       |    Version:
 Keywords:              |       Port:  boost
------------------------+--------------------
 The version in the boost port group, 1.76, was released in April 2021.

-- 
Ticket URL: <https://trac.macports.org/ticket/71748>
MacPorts <https://www.macports.org/>
Ports system for macOS