Require RSocket 1.0 as minimum version

RSocket removed in 1.1 some classes deprecated in 1.0 (see https://github.com/rsocket/rsocket-java/commit/6daa2ebb07c00d6394fef7bb039bf73a935f884e).

Spring Framework deprecated related classes in the 5.2.x line. Because RSocket is still quite new and given the LTS requirements for the 5.3.x line, we'll remove our deprecated classes as well.