Incompatible with Boost 1.71

[cc32d9]

Boost 1.71 is the one delivered in Ubuntu 20.04 libraries. Appbase fails to compile with it. What is the midterm planin supporting Boost?

truncated output:

[ 62%] Building CXX object CMakeFiles/chronicle-receiver.dir/chronicle-receiver/receiver_plugin.cpp.o
In file included from /usr/include/boost/asio/executor.hpp:338,
                 from /usr/include/boost/asio/basic_socket.hpp:27,
                 from /usr/include/boost/asio/basic_datagram_socket.hpp:20,
                 from /usr/include/boost/asio.hpp:24,
                 from /opt/src/eos-chronicle/external/appbase/include/appbase/channel.hpp:7,
                 from /opt/src/eos-chronicle/external/appbase/include/appbase/application.hpp:3,
                 from /opt/src/eos-chronicle/chronicle-receiver/receiver_plugin.hpp:1,
                 from /opt/src/eos-chronicle/chronicle-receiver/receiver_plugin.cpp:3:
/usr/include/boost/asio/impl/executor.hpp: In instantiation of ‘boost::asio::execution_context& boost::asio::executor::impl< <template-parameter-1-1>, <template-parameter-1-2> >::context() [with Executor = std::reference_wrapper<boost::asio::io_context>; Allocator = std::allocator<void>]’:
/usr/include/boost/asio/impl/executor.hpp:177:22:   required from here
/usr/include/boost/asio/impl/executor.hpp:179:22: error: ‘class std::reference_wrapper<boost::asio::io_context>’ has no member named ‘context’
  179 |     return executor_.context();
      |            ~~~~~~~~~~^~~~~~~
/usr/include/boost/asio/impl/executor.hpp: In instantiation of ‘void boost::asio::executor::impl< <template-parameter-1-1>, <template-parameter-1-2> >::on_work_started() [with Executor = std::reference_wrapper<boost::asio::io_context>; Allocator = std::allocator<void>]’:
/usr/include/boost/asio/impl/executor.hpp:167:8:   required from here
/usr/include/boost/asio/impl/executor.hpp:169:15: error: ‘class std::reference_wrapper<boost::asio::io_context>’ has no member named ‘on_work_started’
  169 |     executor_.on_work_started();
      |     ~~~~~~~~~~^~~~~~~~~~~~~~~
/usr/include/boost/asio/impl/executor.hpp: In instantiation of ‘void boost::asio::executor::impl< <template-parameter-1-1>, <template-parameter-1-2> >::on_work_finished() [with Executor = std::reference_wrapper<boost::asio::io_context>; Allocator = std::allocator<void>]’:
/usr/include/boost/asio/impl/executor.hpp:172:8:   required from here
/usr/include/boost/asio/impl/executor.hpp:174:15: error: ‘class std::reference_wrapper<boost::asio::io_context>’ has no member named ‘on_work_finished’
  174 |     executor_.on_work_finished();