[MacPorts] #58856: Boost: update to 1.71.0

[MacPorts]

#58856: Boost: update to 1.71.0
--------------------------+-----------------------
  Reporter:  michaelld    |      Owner:  michaelld
      Type:  enhancement  |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:
      Port:  boost        |
--------------------------+-----------------------
Changes (by michaelld):

 * cc: ryandesign (added)
 * owner:  (none) => michaelld
 * status:  new => assigned


-- 
Ticket URL: <https://trac.macports.org/ticket/58856#comment:1>
MacPorts <https://www.macports.org/>
Ports system for macOS