Warning from Boost- requires C++14

[dfalster]

Recently a warning has appeared during compilation:

   clang++ -arch arm64 -std=gnu++11 -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG -isystem../inst/include/ -I'/Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library/Rcpp/include' -I'/Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library/BH/include' -I/opt/R/arm64/include    -fPIC  -falign-functions=64 -Wall -g -O2  -Wall -pedantic -fdiagnostics-color=always -c RcppR6.cpp -o RcppR6.o
   In file included from RcppR6.cpp:2:
   In file included from ../inst/include/plant.h:21:
   In file included from ../inst/include/plant/strategy.h:8:
   In file included from ../inst/include/plant/uniroot.h:8:
   In file included from /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library/BH/include/boost/math/tools/roots.hpp:19:
   /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/library/BH/include/boost/math/tools/config.hpp:23:6: warning: "The minimum language standard to use Boost.Math will be C++14 starting in July 2023 (Boost 1.82 release)" [-W#warnings]