fix: Keep compatible with old boost versions

[erobot]

Motivation

Keep compatible with old boost versions.

Modifications

Port boost compatible code from branch-3.4 and make minor changes for USE_ASIO.

Code from branch-3.4:

pulsar-client-cpp/lib/ClientConnection.cc

Lines 171 to 177 in 1cb1bf8

	#if BOOST_VERSION >= 107000
	strand_(boost::asio::make_strand(executor_->getIOService().get_executor())),
	#elif BOOST_VERSION >= 106600
	strand_(executor_->getIOService().get_executor()),
	#else
	strand_(executor_->getIOService()),
	#endif

Verifying this change

• Make sure that the change passes the CI checks.

This change is a trivial rework / code cleanup without any test coverage.

Documentation

• doc-required
  (Your PR needs to update docs and you will update later)

• doc-not-needed
  No functionality changed. Just keep the old compatible behavior.

• doc
  (Your PR contains doc changes)

• doc-complete
  (Docs have been already added)

[BewareMyPower]

It's okay to keep compatibility with old boost versions. But the pre-built libraries and dependency files (vcpkg.json or dependencies.yaml) all uses new boost or asio versions. So the compatibility is not guaranteed in future.