deprecation messages for auto_unit_test.hpp seen in build logs.

The following deprecated file usage is mentioned in build logs.

[ 86%] Building CXX object tests/CMakeFiles/app_test.dir/app/main.cpp.o
In file included from /usr/include/boost/config/header_deprecated.hpp:18,
                 from /usr/include/boost/test/auto_unit_test.hpp:16,
                 from /home/ubuntu/23022022/peerplays/tests/benchmarks/genesis_allocation.cpp:30:
/usr/include/boost/test/auto_unit_test.hpp:17:1: note: #pragma message: This header is deprecated. Use This header is deprecated. Please use <boost/test/unit_test.hpp> instead. instead.
   17 | BOOST_HEADER_DEPRECATED( "This header is deprecated. Please use <boost/test/unit_test.hpp> instead." )
      | ^~~~~~~~~~~~~~~~~~~~~~~
[ 86%] Building CXX object tests/CMakeFiles/chain_bench.dir/benchmarks/main.cpp.o